WO2022229661A1

WO2022229661A1 - Laminated products and methods for their production

Info

Publication number: WO2022229661A1
Application number: PCT/GB2022/051103
Authority: WO
Inventors: Dilip Mistry; Daniel MCALLISTER
Original assignee: Dm Flexibles Ltd
Priority date: 2021-04-29
Filing date: 2022-04-29
Publication date: 2022-11-03
Also published as: GB202106137D0; EP4330033A1

Abstract

Laminated products having a water-soluble polymer layer fully or partially laminated to a plant-based fibre layer, are provided. Methods of manufacturing such products and their uses are also provided.

Description

LAMINATED PRODUCTS AND METHODS FOR THEIR PRODUCTION

Field of the Invention This invention relates to a laminated product, particularly although not exclusively a product having a water-soluble polymer layer is laminated to a plant-based fibre layer. The invention also relates to method of manufacturing such products and their uses. Background to the Invention

The environmental effect of some synthetic organic polymers (commonly referred to as “plastics”) is an ever increasing problem on a global scale. In particular, the lack of biodegradability of polyolefin polymers such as polyethylene and polypropylene causes major problems with relation to the disposal of products containing such polymers. Frequently, products containing such polymers ends up in landfill or in the marine environment, causing significant detrimental effects to marine life.

In view of these well-documented problems, there have been significant recent efforts to replace or reduce the amount of synthetic organic polymers, in particular polyolefin polymers, in packaging. Many of these efforts have been focused on the use of plant-based fibre products, in particular paper or card, as a whole or partial replacement for synthetic polymers. Such materials are more easily recyclable and therefore minimises the amount of waste which requires disposal.

However, many products are on the market which are packaged using laminated materials in which a plant-based fibre layer, such as paper or card, is adhered to a layer of a synthetic organic polymer, such as a polyolefin polymer. One example of such product is the well-known container for containing sandwiches. While a significant proportion of the packaging is made from card, such containers typically have an aperture covered by a clear layer of synthetic organic polymer to which the card layer is adhered, and through which the contents of the container can be seen. The recycling of such containers presents particular challenges, in that it is difficult to separate the synthetic polymer layer from the card layer after use. For this reason, typically the whole container is disposed of in non-recyclable waste, meaning that neither the card nor the synthetic organic polymer layer is recycled. Products, especially packaging products, which have greater recyclability of all components would therefore be highly desirable.

WO 2017/046361 describes a method for the manufacture of a plasticised poly(vinyl alcohol) polymer mixture, the method comprising the steps of: introducing a poly(vinyl alcohol) polymer comprising at least 98wt% polyvinyl alcohol or a blend of the polymer into a mixing reactor; wherein the mixing reactor comprises a blending chamber having a primary inlet, a primary outlet and at least two inter-engaging components extending between the primary inlet and primary outlet, the components being arranged to apply a shearing force to the polymer while the polymer is conveyed by the components from the inlet through a reaction zone to the outlet; one or more secondary inlets located downstream from the primary inlet for introducing reactants comprising a processing agent and a plasticiser to the chamber to form a reaction mixture; wherein the blending chamber comprises a plurality of heated regions arranged so that the mixture is subjected to a controlled temperature profile; a secondary outlet located between the reaction zone and primary outlet arranged to allow removal of processing agent from the chamber; reacting a reaction mixture comprising the processing agent, plasticiser and polymer in the reaction zone to form plasticised polymer; wherein when the processing agent is water, the amounts of water is from 3wt% to 18wt%; and allowing the plasticised polymer to pass from the primary outlet. However, it does not describe the lamination of a poly(vinyl alcohol) film to a plant-based fibre material such as paper or card, nor a laminated product produced therefrom.

EP0530662A describes a laminated material for packaging use, principally for the packaging of liquid foods. The material is formed of a multilayer structure, and is constructed by laminating poly(vinyl alcohol) or other water-soluble, thermoplastic resin layers on both sides of a paperboard base material layer. However, the laminated material of EP0530662A also includes a thermoplastic synthetic resin layer further laminated on one side of the paperboard and poly(vinyl alcohol) layer, and a liquid-resistant thermoplastic resin, which may be polyethylene, further laminated on the other side of the poly(vinyl alcohol) layer. The inclusion of polyethylene or other non-water-soluble thermoplastic resin layers in such a laminated material runs contrary to the sustainability and ease of recycling (particularly through repulping) objectives of the present invention. EP0798231 A describes a laminated product prepared by laminating a water-soluble poly(vinyl alcohol) film on a paper board, using a wet laminator. The paper base has on one surface a poly(vinyl alcohol) layer coated with poly(vinyl alcohol) liquid which acts as an adhesive, and the poly(vinyl alcohol) film is stacked on the paper board via the poly(vinyl alcohol) layer. The laminated product is sealed at its periphery using heat seal portions made by solvent welding of stacked poly(vinyl alcohol), to prepare airbags for use as shock absorbers for internal packaging of a product which already has an outer casing, such as a cardboard container. However, the use of poly(vinyl alcohol) as an adhesive to bond the paper and the poly(vinyl alcohol) film layers together would render this product unsuitable for recycling via repulping, as the poly(vinyl alcohol) adhesive would not be washed away in the repulping.

EP0545277A describes packaging bodies made from cardboard and paper products, provided with transparent parts, such as containers with transparent windows. The transparent windows are made from amylose-containing compounds. According to this publication, the transparent parts can be destroyed or dissolved in water after the packaging has been used and the cellulose/wood pulp content can be fed to a waste paper treatment plant. The document describes generally, but does not specifically disclose or exemplify, that the composition of the transparent layer may optionally contain other polymers including poly(vinyl alcohol). However, the amylose- containing compounds used to form the transparent material exhibit a disadvantage in that the transparent layer is liable to dissolve on inadvertent wetting through rainwater or other accidentally applied water, thus rendering it unsuitable for many food packaging applications.

JP 2017-77A describes a water-soluble laminate made of a water-soluble polymer material, such as poly(vinyl alcohol), comprising a water-soluble reticulated sheet and a poly(vinyl alcohol)-based water-soluble film. The water-soluble laminate is stated to be useful as a vegetation sheet. The vegetation sheet may additionally comprise a sheet of fibrous material, such as paper, such that a plant may be sandwiched between the water-soluble laminate and the sheet made of the fibrous material. However, it does not describe a laminated product in which the layer of fibrous material is partially or fully laminated to the layer of water-soluble polymer material. In particular, it does not describe a laminated product in which the layer of fibrous material is partially or fully adhered to the layer of water-soluble polymer material. Summary of the Invention

According to a first aspect of the invention, there is provided a method of preparing a film of a water-soluble polymer, the method comprising: (a) extruding the water-soluble polymer by passing the water-soluble polymer through an elongate chamber under the application of heat and one or more rotating screws, so as to partially or wholly melt the water-soluble polymer;

(b) applying pressure to the melted water-soluble polymer to form the film. According to a second aspect of the invention, there is provided a water-soluble polymer in the form of a film, obtained or obtainable by the method of the first aspect of the invention.

According to a third aspect of the invention, there is provided a laminated product comprising:

(a) one or more layers of plant-based fibre sheet material, having fully or partially laminated thereto

(b) one or more layers of water-soluble polymer in the form of a film.

In one embodiment of this aspect, the water-soluble polymer layer (b) is the water- soluble polymer film according to the second aspect.

According to a fourth aspect of the invention, there is provided a container having:

(a) a structure of plant-based fibre sheet material, having fully or partially laminated thereto (b) a layer of water-soluble polymer in the form of a film.

According to a fifth aspect of the invention, there is provided a method of producing the laminated product of the third aspect or the container of the fourth aspect, the method comprising:

(i) providing layer or structure (a); and

(ii) applying layer (b) such that it fully or partially laminates to layer or structure (a). According to a sixth aspect of the invention, there is provided a method of producing the laminated product of the third aspect or the container of the fourth aspect, the method comprising: (i) providing layer or structure (a); and (ii) producing layer (b) by extrusion of the water soluble polymer onto layer or structure (a) such that it laminates directly thereto.

According to a seventh aspect of the invention, there is provided a laminated product comprising:

(b) one or more layers of water-soluble polymer film formed from a composition comprising poly(vinyl alcohol), wherein the composition does not contain amylose, wherein layer (b) is present on only one side of layer (a); and wherein layer (b) is adhered to layer (a) using an adhesive which does not contain poly(vinyl alcohol).

According to an eighth aspect of the invention, there is provided a container having:

(a) a structure of plant-based fibre sheet material, having fully or partially laminated thereto

(b) a layer of water-soluble polymer in the form of a film; formed from a composition comprising poly(vinyl alcohol), wherein the composition does not contain amylose, wherein layer (b) is present on only one side of structure (a); and wherein layer (b) is adhered to layer (a) using an adhesive which does not contain poly(vinyl alcohol).

According to a ninth aspect of the invention, there is provided a method of producing the laminated product of the seventh aspect or the container of the eighth aspect, comprising:

(i) providing layer or structure (a);

(ii) applying an adhesive to one side of layer or structure (a) and

(iii) applying the adhesive-bearing side of layer or structure (a) to layer (b) such that it fully or partially adheres to layer or structure (a).

These and further aspects are described in more detail below.

Advantages and Surprising Findings

It has been surprisingly found by the present inventors that applying one or more layers of water-soluble polymer, particularly although not exclusively poly(vinyl alcohol) in the form of a film to one or more layer of plant-based fibre material (particularly although not exclusively paper or card) results in a laminated product which is both suitable as a packaging material and can be easily processed after use by simply applying water to the laminated product. Applying water to the product causes the water-soluble polymer layer to dissolve, thereby meaning that requires no mechanical separation from the plant-based fibre sheet material layer, thereby allowing the plant-based fibre sheet material layer to be recycled (when this material is paper or card, typically by repulping). This enables the entire product to be more easily recyclable, and avoids it being sent to landfill for disposal, enabling significant environmental benefits.

In addition, it has surprisingly been found by the present inventors that the inclusion of a plasticiser in the water-soluble polymer composition serves to strengthen the composition when formed into a film as described below. In particular, the application of a plasticiser renders the film resistant to degradation when exposed to light and/or inadvertent wetting such as rainwater, but the film can be still separated from the plant-based fibre sheet layer by the application of water in typical repulping conditions.

Brief Description of the Drawings

Fig. 1 shows apparatus suitable for producing a film of water-soluble polymer according to the invention;

Fig. 2 shows a laminated product according to an embodiment of the present invention, wherein the plant-based fibre sheet material is adhered to the water- soluble polymer film layer by means of an adhesive layer;

Fig. 2A shows a laminated product according to an alternative embodiment of the present invention, wherein the plant-based fibre sheet material is adhered to the water-soluble polymer film layer by means of an adhesive layer;

Fig. 2B shows a laminated product according to a further alternative embodiment of the present invention wherein the plant-based fibre sheet material is adhered to the water-soluble polymer film layer by means of a first and a second adhesive layer; Fig. 2C shows a laminated product according to an alternative embodiment of the present invention, wherein the plant-based fibre sheet material is adhered to a metal layer by means of a first adhesive layer, and the metal layer is adhered to the water- soluble polymer film layer by means of a second adhesive layer; Fig. 3 shows a typical container suitable for containing pre-packed sandwiches having a viewing aperture covered by a water-soluble polymer layer according to an embodiment of the present invention;

Fig. 4 shows the lamination process for producing a laminated product according to one embodiment of the present invention;

Fig. 5 shows the process for lamination according to another embodiment of the present invention by co-extruding the water-soluble polymer layer directly onto the plant-based fibre sheet layer;

Fig. 6 is a schematic diagram of a physical vapour deposition process for applying the metal layer according to one embodiment of the present invention; and Fig. 7 shows a process and apparatus for application of the metal layer according to one embodiment of the present invention.

Detailed Description

Water-Soluble Polymer

The polymer used in the film of the present invention, and the laminated products produced by adhering one or more layers of the polymer wholly or partially to one or more layers of plant-based fibre, is a water-soluble polymer. As indicated above, the use of water-soluble polymers in such laminated products allows the polymer layer to be easily separated from the plant-based fibre layer by simple dissolution in water, thereby allowing both component layers of the laminated product to be recycled.

Examples of water-soluble polymers are known to those skilled in the art, and include poly(vinyl alcohol), poly(vinyl esters) such as (polyvinyl acetate), poly(acrylamides), poly(acrylic acid), quaternary ammonium polymers, polyamines, polyethylene glycols, polyvinyl methyl ether / maleic anhydride, and carboxypolymethylene.

In one embodiment, the water-soluble polymer comprises poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer consists essentially of poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer consists of poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer is poly(vinyl alcohol) (PVOH). Poly(vinyl alcohol) is particularly suitable for the manufacture of the laminated products in view of its good adhesion properties to plant-based fibre layers such as paper and card, and its ready solubility in water to enable it to be easily separated from these layers by dissolution in water. It is also non-toxic and has no ecotoxicity in a marine environment, and biodegrades readily, at a similar rate to cellulose.

As is well known to the person skilled in the art, poly(vinyl alcohol) is typically produced by a two-step process. The first step of the process typically comprises polymerisation of a vinyl ester monomer, typically vinyl acetate, to produce a poly(vinyl ester), typically poly(vinyl acetate). The second step of this process typically comprises hydrolysis of the ester bonds in the poly (vinyl ester) to produce poly(vinyl alcohol). This may be carried out under acid or alkaline conditions, typically alkaline conditions. Typically, the alkali is an alkali metal hydroxide, such a sodium hydroxide or potassium hydroxide.

Poly(vinyl alcohol) has the general structure shown below (the vinyl ester monomer in this case being vinyl acetate):

Poly(vinyl alcohol) is commercially available from a wide range of suppliers in a number of grades. Typically, poly(vinyl alcohol) is graded by its molecular weight and degree of hydrolysis. A wide range of poly(vinyl alcohol) grades are available, depending on the performance properties required for the specific applications and varying in properties such as water solubility, abrasion resistance, tensile strength, adhesive barrier and bonding properties, grease or oil resistance and film forming qualities.

In one embodiment, the poly(vinyl alcohol) is ultra low viscosity poly(vinyl alcohol). Typically such a grade of poly(vinyl alcohol) has a viscosity of 3 to 4 cps, a degree of polymerisation of 150 to 300, and a weight average molecular weight of 13,000 to 23,000. In one embodiment, the poly(vinyl alcohol) is low viscosity poly(vinyl alcohol). Typically such a grade of poly(vinyl alcohol) has a viscosity of 5 to 6 cps, a degree of polymerisation of 350 to 600, and a weight average molecular weight of 31 ,000 to 50,000.

In one embodiment, the poly(vinyl alcohol) is medium viscosity poly(vinyl alcohol). Typically such a grade of poly(vinyl alcohol) has a viscosity of 22 to 30 cps, a degree of polymerisation of 1000 to 1500, and a weight average molecular weight of 85,000 to 124,000.

In one embodiment, the poly(vinyl alcohol) is high viscosity poly(vinyl alcohol). Typically such a grade of poly(vinyl alcohol) has a viscosity of 45 to 72 cps, a degree of polymerisation of 1600 to 2200, and a weight average molecular weight of 146,000 to 186,000.

The degree of hydrolysis of the poly(vinyl alcohol) is the mole percentage of ester groups which are hydrolysed to provide alcohol functional groups on the polymer. This can be calculated as shown below (where m and n are as shown above on the general structure):

Degree of hydrolysis (mol%) = [m / (m+n)] x 100

In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 80 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 85 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 90 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 91 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 92 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 93 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 94 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 95 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 96 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 97 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 98 mol%. In one embodiment the poly(vinyl alcohol) has a degree of hydrolysis of at least 99 mol%. Typically, the poly(vinyl alcohol) is supplied to the extruder in the form of a resin, suitably in the form of pellets which can easily be introduced into the extruder.

Examples of suitable commercially available poly(vinyl alcohol) resins include those of the HYDROPOL® range (Aquapak Polymers Ltd., UK), especially the HYDROPOL® 33100 series, and POVAL (Kuraray Co., Ltd., Japan).

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) one or more ingredients other than poly(vinyl alcohol).

In one embodiment, the poly(vinyl alcohol) present in the water-soluble polymer composition is a single grade of poly(vinyl alcohol). In one embodiment, the poly(vinyl alcohol) present in the water-soluble polymer composition is a mixture of different grades of poly(vinyl alcohol). As indicated above, the various grades of poly(vinyl alcohol) present in a mixture may be differentiated by a number of factors, including but not limited to molecular weight, viscosity and/or degree of hydrolysis).

The water-soluble polymer composition may contain further ingredients in addition to the poly(vinyl alcohol). Examples of additional ingredients include plasticisers (such as polyhydric alcohols, one particular example of which is glycerol) and water.

In one embodiment, the composition contains more than 50% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 60% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 70% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 75% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 80% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 85% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 90% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 95% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, composition contains more than 97% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 98% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 99% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains more than 99.5% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains 100% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition.

In one embodiment, the composition contains 50 to 99% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains 60 to 98% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains 70 to 97% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains 75% to 95% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition. In one embodiment, the composition contains 80 to 90% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition.

The composition may contain other ingredients in addition to the water-soluble polymer itself. Examples of additives commonly added to water-soluble polymer compositions intended for use as films, especially poly(vinyl alcohol) compositions intended for use as films, include water; polyhydric alcohols such as glycerol, organic acids, especially carboxylic acids such as acetic acid; anti-block agents (the function of which is to prevent the plastic layers from sticking together (blocking) when rolled up, examples of which include paraffinic waxes, fatty acid soaps, and ethylene oxide- or propylene oxide-based materials), slip agents (the function of which is to aid opening of the packaging and allow items to slide in smoothly, examples of which include polyols, especially C polyols such as glycerol, propylene glycol, butylene glycol and hexylene glycol, and polysorbates) and ultraviolet inhibitors (the function of which is to protect the polymer from ultraviolet radiation, which can weaken its strength and fade its colour, examples of which include benzophenones, benzotriazoles and benzoic acids, and hindered amine light stabilisers).

In one embodiment, the composition contains water. In one embodiment, the composition contains up to 30% by weight water as a proportion of the total weight of the composition. In one embodiment, composition contains up to 20% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 10% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 5% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 2% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 1% by weight water as a proportion of the total weight of the composition.

In one embodiment, the composition contains from 1% to 30% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains from 2% to 20% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains 3 to 15% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains 4 to 12% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains 5 to 10% by weight water as a proportion of the total weight of the composition. In one embodiment, the composition contains 5%, 6%, 7%, 8%, 9% or 10% by weight water as a proportion of the total weight of the composition.

In one embodiment, the composition contains a plasticiser. It has surprisingly been found according to the present invention that the inclusion of a plasticiser in the water-soluble polymer composition serves to strengthen the composition when formed into a film as described below. In particular, the application of a plasticiser renders the film resistant to degradation when exposed to light and/or inadvertent wetting such as rainwater, but the film can be still separated from the plant-based fibre sheet layer by the application of water in typical repulping conditions.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser; and

(c) water. In one embodiment, the composition contains up to 30% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 20% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 10% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 5% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 2% by weight plasticiser as a proportion of the total weight of the composition.

In one embodiment, the composition contains up to 1% by weight plasticiser as a proportion of the total weight of the composition.

In one embodiment, the composition contains from 1% to 30% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains from 2% to 20% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains 3 to 15% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains 4 to 12% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains 5 to 10% by weight plasticiser as a proportion of the total weight of the composition. In one embodiment, the composition contains 5%, 6%, 7%, 8%, 9% or 10% by weight plasticiser as a proportion of the total weight of the composition.

Examples of plasticisers are well known to those skilled in the art, and include polyhydric alcohols, polyethylene glycols, glycerol, diols or triols, for example, propylene glycol, ethylene glycol, polyethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane; esters thereof such as triethylene glycol di-2-hexanoate and mixtures thereof; phthalate-based plasticizers, such as low molecular weight ortho phthalates including diisobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBzP), and bis(2-ethylhexyl) phthalate (DEHP), high molecular weight ortho phthalates such as diisononyl phthalate (DINP), bis(2-propylheptyl) phthalate (DPHP), diisodecyl phthalate (DIDP), diisoundecyl phthalate (DIUP), and ditridecyl phthalate (DTDP); trimellitates such as tri-(2-ethy I hexy I) tri m el I itate (TEHTM or TOTM), tri- (isononyl)trimellitate (TINTM), tri-(isodecyl)trimellitate (TIDTM), tri-(isotridecyl)- trimellitate (TITDTM); adipates such as bis(2-ethylhexyl)adipate (DEHA); sebacates such as dibutyl sebacate (DBS), di-(2-ethylhexyl)sebacate or di-octyl sebacate (DOS); glycerol triacetate (triacetin); alkyl citrates, such as triethyl citrate (TEC), acetyl triethyl citrate (ATEC), tributyl citrate (TBC), tri-(2-ethylhexyl)citrate (TOC), acetyl trioctyl citrate (ATOC), trihexyl citrate (THC), acetyl trihexyl citrate (ATHC), butyryl trihexyl citrate (BTHC) or trihexyl o-butyryl citrate; vegetable oil based plasticizers such as epoxidized soybean oil (ESBO or ESO) and epoxidized linoleic oil (ELO); azelates; dibenzoates; terephthalates such as bis(2 ethyl hexyl terephthalate (DEHT) and dibutyl terephthalate (DBT); 1,2-cyclohexane dicarboxylic acid diisononyl ester; alkyl sulphonic acid phenyl ester (ASE).

In one embodiment, the plasticiser comprises a polyhydric alcohol. In one embodiment, the plasticiser consists essentially of a polyhydric alcohol. In one embodiment, the plasticiser consists of a polyhydric alcohol. In one embodiment, the polyhydric alcohol is other than poly(vinyl alcohol).

In one embodiment, the plasticiser comprises a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof. In one embodiment, the plasticiser consists essentially of a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof. In one embodiment, the plasticiser consists of a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

In one embodiment, the plasticiser comprises glycerol. In one embodiment, the plasticiser consists essentially of glycerol. In one embodiment, the plasticiser consists of glycerol.

In one embodiment, the composition contains up to 30% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 20% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 10% by weight glycerol as a proportion of the total weight of the water-soluble polymer film.

In one embodiment, the composition contains up to 5% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 2% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains up to 1% by weight glycerol as a proportion of the total weight of the composition.

In one embodiment, the composition contains from 1% to 30% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains from 2% to 20% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains 3 to 15% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains 4 to 12% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains 5 to 10% by weight glycerol as a proportion of the total weight of the composition. In one embodiment, the composition contains 5%, 6%, 7%, 8%, 9% or 10% by weight glycerol as a proportion of the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting essentially of glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting of glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, which is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof. In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting essentially of glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting of glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser, which is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser, comprising glycerol; and

(c) water.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser, consisting essentially of glycerol; and

(c) water.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser, consisting of glycerol; and

(c) water.

In one embodiment, there is provided a composition comprising: (a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the composition; and

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 70 to 97% by weight based on the total weight of the composition; and

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 75 to 95% by weight based on the total weight of the composition; and

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the composition; and

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

In one embodiment, there is provided a composition comprising: (a) poly(vinyl alcohol) in an amount of 75 to 95% by weight based on the total weight of the composition; and

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition, wherein the plasticiser is glycerol.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition, wherein the plasticiser is glycerol.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition, wherein the plasticiser is glycerol.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the composition;

(b) a plasticiser, in an amount of 1 to 30% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 1 to 30% by weight based on the total weight of the composition. In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 70 to 97% by weight based on the total weight of the composition;

(b) a plasticiser, in an amount of 3 to 15% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 3 to 15% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 75 to 95% by weight based on the total weight of the composition;

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 4 to 12% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(a) poly(vinyl alcohol) in an amount of 75 to 95% by weight based on the total weight of the composition; and (b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition; and

(c) water in an amount of 1 to 30% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition; and

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition; and

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 1 to 30% by weight based on the total weight of the composition, wherein the plasticiser is glycerol; and

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 3 to 15% by weight based on the total weight of the composition, wherein the plasticiser is glycerol; and (c) water in an amount of 3 to 15% by weight based on the total weight of the composition.

In one embodiment, there is provided a composition comprising:

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the composition, wherein the plasticiser is glycerol; and

In one embodiment, the composition does not contain starch. In one embodiment, the composition does not contain modified starch. In one embodiment, the composition does not contain hydroxypropyl corn starch. In one embodiment, the composition does not contain amylose.

In one embodiment, the composition contains less than 10% by weight starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 5% by weight starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 2% by weight starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 1% by weight starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 0.5% by weight starch as a proportion of the total weight of the composition. In one embodiment, the composition does not contain starch.

In one embodiment, the composition contains less than 10% by weight modified starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 5% by weight modified starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 2% by weight modified starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 1% by weight modified starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 0.5% by weight modified starch as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 10% by weight amylose as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 5% by weight amylose as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 2% by weight amylose as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 1% by weight amylose as a proportion of the total weight of the composition. In one embodiment, the composition contains less than 0.5% by weight amylose as a proportion of the total weight of the composition. In one embodiment, the composition does not contain amylose.

Method of Preparation of Water-Soluble Polymer Film

According to the present invention, the water-soluble polymer is extruded and subject to processing to form a film of the water-soluble polymer. This film is then suitable for adhering wholly or partially to a layer of plant-based fibre material to form the laminated products of the present invention.

Thus, in one aspect of the invention, there is provided a method of preparing a film of a water-soluble polymer, the method comprising:

(a) extruding the water-soluble polymer by passing the water-soluble polymer through an elongate chamber under the application of heat and one or more rotating screws, so as to partially or wholly melt the water-soluble polymer; and

(b) applying pressure to the melted water-soluble polymer to form the film.

Step (b) comprises applying pressure to the water-soluble polymer to form the film.

In one embodiment, step (b) comprises shaping the water-soluble polymer to form the film.

In one embodiment, step (b) comprises the following:

(b1) passing the wholly or partially melted water soluble polymer through an aperture; (b2) cooling the water soluble polymer;

(b3) introducing air into the water-soluble polymer so as to form a bubble of the water-soluble polymer; and

(b4) collapsing the bubble of the water-soluble polymer to form a film. In the methods described above, the water-soluble polymer may be used alone, or may form part of a composition as defined above, either in its broadest aspect or any of the preferred aspects.

As is generally known to the person skilled in the art, typically, extrusion comprises heating the material to be extruded while passing the material through an elongate chamber (typically a barrel) under the application of one or more rotating screws, so as to partially or wholly melt the material. In a subsequent step, the partially or wholly melted material is then passed through a die so as to form the material into the desired shape.

In one embodiment, the water-soluble polymer to be extruded is heated prior to being passed through the extruder. In one embodiment, the water-soluble polymer to be extruded is heated while being passed through the extruder.

The temperature at which the extrusion is carried out may vary based on the type grade and melting point of the water-soluble polymer, the other conditions of the extrusion process, and the final intended product. In one embodiment, the extrusion is carried out at a temperature of 0 to 300°C. In one embodiment, the extrusion is carried out at a temperature of 50 to 280°C. In one embodiment, the extrusion is carried out at a temperature of 80 to 290°C. In one embodiment, the extrusion is carried out at a temperature of 100 to 280°C. In one embodiment, the extrusion is carried out at a temperature of 110 to 270°C. In one embodiment, the extrusion is carried out at a temperature of 120 to 260°C. In one embodiment, the extrusion is carried out at a temperature of 130 to 250°C. In one embodiment, the extrusion is carried out at a temperature of 140 to 240°C.

In one embodiment, the extruder may comprise one or more extrusion zones having different temperatures, the temperature increasing from the inlet of the extruder, up to a maximum point within the extruder, and then lowering again near the outlet of the extruder.

The pressure at which the extrusion is carried out may vary based on the type and grade of the water-soluble polymer, the other conditions of the extrusion process, and the final intended product to which it is applied. In one embodiment, the extrusion is carried out at a pressure of 10 to 50 MPa. In one embodiment, the extrusion is carried out at a pressure of 19 to 27 MPa.

The water-soluble polymer may be subject to a single extrusion, using a single screw, or multiple extrusions using multiple screws. When multiple screws are in operation, the screw diameters, rotational speeds and operating conditions may be the same or different. In one embodiment, the extruder is a single-screw extruder. In another embodiment, the extruder is a twin-screw extruder.

The length/diameter (L/D) ratio of the elongate chamber (barrel) of the extruder may vary based on the other conditions of the extrusion process, the type and grade of the water-soluble polymer, and the final intended product to which it is applied. In one embodiment the extruder has a length/diameter ratio of between 10:1 and 50:1.

In one embodiment the extruder has a length/diameter ratio of between 20:1 and 40:1.

The diameter of the screw or screws used in the extruder may vary based on the other conditions of the extrusion process, the type and grade of the water-soluble polymer, and the final intended product to which it is applied. In one embodiment the rotating screw or screws used in the extruder have a diameter of 1 to 20 cm. In one embodiment the rotating screw or screws used in the extruder have a diameter of 2 to 15 cm. In one embodiment the rotating screw or screws used in the extruder have a diameter of 4 to 10 cm.

The rotational speed of the screw or screws used in the extruder may vary based on the other conditions of the extrusion process, the type and grade of the water-soluble polymer, and the final intended product to which it is applied. In one embodiment the rotating screw or screws used in the extruder have a rotational speed of 10 to 300 rpm. In one embodiment the rotating screw or screws used in the extruder have a rotational speed of 30 to 200 rpm. In one embodiment the rotating screw or screws used in the extruder have a rotational speed of 50 to 100 rpm. The rate at which the water-soluble polymer is introduced into the extruder may vary based on the size of the extruder, other conditions of the extrusion process, the type and grade of the water-soluble polymer, and the final intended product to which it is applied. In one embodiment the water-soluble polymer is introduced into the extruder at a rate of 100 to 1000 kg/hour. In one embodiment the water-soluble polymer is introduced into the extruder at a rate of 300 to 750 kg/hour.

After passing through the extruder, the wholly or partially melted water soluble polymer is passed through an aperture of a suitable shape to form a water-soluble polymer of the desired shape. Typically, the aperture forms part of a die through which the wholly or partially melted water soluble polymer passes. The walls of the die define the shape of the aperture.

The aperture of the die may vary in shape depending on the manner in which the melted water-soluble polymer is to be further processed on exiting the die. In one embodiment, the aperture of the die may be a shape selected from circular, elliptical or polygonal (e.g. triangular, quadrilateral, or hexagonal). In one embodiment, the aperture is circular. Such shapes are particularly preferred when the water-soluble polymer is blown and then subsequently pressed to form a film on exiting the die.

In one embodiment, the aperture of the die is an elongate slit, the walls of the die converging towards this slit. Such a shape is particularly preferred when the water- soluble polymer forms a film directly on exiting the die, as the film can be subsequently laminated directly onto the plant-based fibre sheet material to form the laminated product of one embodiment of the present invention.

The diameter of the aperture may be any suitable for producing a water-soluble polymer suitable for subsequent processing into a film. It may vary depending on the size of the extruder. In one embodiment the aperture has a diameter of 10 to 60 cm.

After passing through the aperture, the water-soluble polymer is then cooled. The temperature to which the water-soluble polymer is cooled may vary depending on type and grade of the water-soluble polymer, and the final intended product to which it is applied. In one embodiment, the water-soluble polymer is cooled to a temperature of -10 to 50 °C. In one embodiment, the water-soluble polymer is cooled to a temperature of 10 to 30 °C. In one embodiment, air is introduced into the water-soluble polymer such that it is formed into a bubble. This process is referred to as “blowing” the polymer. Typically, this occurs when the aperture of the die is circular or elliptical, such that the water- soluble polymer bubble forms around the walls of the die. The bubble is then urged towards the means for collapsing it to form the film.

In one embodiment, the water-soluble polymer is cooled by an air ring. This performs the dual function of cooling the polymer and introducing air into the polymer to form the bubble.

The blow-up ratio of the bubble (defined as the bubble diameter divided by the die diameter) is typically 1.2 to 6, preferably 2 to 4.5. In one embodiment, the polymer is blown once to create a first bubble, and then the bubble is stretched to create a second bubble of a higher blow-up ratio.

In one embodiment, the bubble is supported by a structure which surrounds the circumference of the bubble, for example with a stabilizing cage.

Following formation of the bubble, the bubble is then collapsed such that the outer surfaces of the bubble are brought together to form a film. Typically, this step is carried out by the application to the bubble of a frame, the elements of which converge such that in use the surfaces of the bubble are urged towards the convergence and are brought together to form a film.

Following this step, the film may be passed between elements, such as nip rolls, to press the water-soluble polymer together to form the film. The film may then pass through further rolls, and/or be wound to form a reel.

The process is shown generally in Fig. 1. The water-soluble polymer is fed into the system, for example via dosing system 12, into extruder 14, comprising elongate barrel 16 and equipped with rotating screw 17. During this process the water-soluble polymer may be heated via heating elements 18a, 18b, 18c, 18d, and/or cooled by cooling fans 19a, 19b, 19c, 19d. After passing through this chamber under the application of heat and the rotating screws, the melted water-soluble polymer is fed through die 20 (which in this particular example may have a circular aperture). The water-soluble polymer may initially be cooled by cooling fans 21a, 21b, 21c. The water-soluble polymer is then cooled by air ring 22 to produce a bubble 24 of water- soluble polymer, which is supported through stabilizing cage 26. The bubble then comes into contact with collapsing frame 28 which converges towards plane 30 to bring the outer surfaces of the bubble together to form the film 32. It is further pressed together using nip rolls 34 and subsequently passes through further rolls 36a, 36b, 36c and is wound to form a reel using winder 38.

Water-Soluble Polymer Film The invention also provides a water-soluble polymer in the form of a film, obtained or obtainable by the method of the invention.

In one embodiment, the water-soluble polymer comprises poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer consists essentially of poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer consists of poly(vinyl alcohol) (PVOH). In one embodiment, the water-soluble polymer is poly(vinyl alcohol) (PVOH). The poly(vinyl alcohol) may be as defined and exemplified above, either in its broadest aspect or a preferred aspect. In one embodiment of the water-soluble polymer film, the water-soluble polymer, typically poly(vinyl alcohol), may be present alone. In one embodiment of the water- soluble polymer film, the water-soluble polymer, typically poly(vinyl alcohol), is present as part of a water soluble polymer film composition together with other ingredients. In one embodiment, the water-soluble polymer film composition may have a composition as defined above in relation to the starting polymer composition from which it is extruded, either in its broadest aspect or any of the preferred aspects. However, when water and/or polyhydric alcohols, such as glycerol, are present in the starting composition, evaporation of some of either or both of these ingredients may occur during the extrusion process to form the film, such that the water-soluble polymer film composition contains less water and/or less polyhydric alcohols than the starting composition from which it is extruded. Typically, around 10 to 15% by weight, such as 12% by weight, of the water present in the starting polymer composition evaporates during extrusion. Typically, around 15 to 55% by weight, such as 20% by weight, of the polyhydric alcohol (such as glycerol) present in the starting polymer composition evaporates during extrusion. In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol); and

(b) one or more ingredients other than poly(vinyl alcohol).

In one embodiment, the poly(vinyl alcohol) present in the water-soluble polymer film composition is a single grade of poly(vinyl alcohol). In one embodiment, the poly(vinyl alcohol) present in the water-soluble polymer film composition is a mixture of different grades of poly(vinyl alcohol). As indicated above, the various grades of poly(vinyl alcohol) present in a mixture may be differentiated by a number of factors, including but not limited to molecular weight, viscosity and/or degree of hydrolysis).

The water-soluble polymer film composition may contain further ingredients in addition to the poly(vinyl alcohol). Examples of additional ingredients include plasticisers (such as polyhydric alcohols, one particular example of which is glycerol) and water.

In one embodiment, the water soluble polymer film composition contains more than 50% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 60% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 70% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 75% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 80% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 85% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 90% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 95% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 97% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 98% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 99% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains more than 99.5% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 100% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition.

In one embodiment, the water soluble polymer film composition contains 50 to 99% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 60 to 98% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 70 to 97% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 75% to 95% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 80 to 90% by weight poly(vinyl alcohol) as a proportion of the total weight of the water soluble polymer film composition.

The water soluble polymer film composition may contain other ingredients in addition to the water-soluble polymer itself. Examples of additives commonly added to water-soluble polymer compositions include those defined and exemplified above in relation to the starting polymer composition from which the film is extruded.

In one embodiment, the water soluble polymer film composition contains water. In one embodiment, the water soluble polymer film composition contains up to 30% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 20% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 10% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 5% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 2% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 1% by weight water as a proportion of the total weight of the water soluble polymer film composition.

In one embodiment, the water soluble polymer film composition contains from 0.5% to 30% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains from 1% to 20% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 2 to 14% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 3 to 13% by weight water as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 4%, 5%, 6%, 7%, 8%, 9% or 10% by weight water as a proportion of the total weight of the water soluble polymer film composition.

In one embodiment, the composition contains a plasticiser. As indicated above, it has surprisingly been found according to the present invention that the inclusion of a plasticiser in the water-soluble polymer film composition serves to strengthen the film. In particular, the application of a plasticiser renders the film resistant to degradation when exposed to light and/or inadvertent wetting such as rainwater, but the film can be still separated from the plant-based fibre sheet layer by the application of water in typical repulping conditions.

In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser. In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol);

(b) a plasticiser; and

(c) water.

In one embodiment, the water soluble polymer film composition contains up to 30% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 20% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 10% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 5% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 2% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 1 % by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition.

In one embodiment, the water soluble polymer film composition contains from 0.5% to 30% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains from 1% to 20% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 2 to 14% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 3 to 13% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 4%, 5%, 6%, 7%, 8%, 9% or 10% by weight plasticiser as a proportion of the total weight of the water soluble polymer film composition.

Examples of plasticisers are well known to those skilled in the art, and include those defined and exemplified above in relation to the plasticisers present in the starting polymer composition. In one embodiment, the water soluble polymer film composition contains up to 30% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 20% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 10% by weight glycerol as a proportion of the total weight of the water-soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 5% by weight glycerol as a proportion of the water soluble polymer film total weight of the composition. In one embodiment, the water soluble polymer film composition contains up to 2% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains up to 1 % by weight glycerol as a proportion of the total weight of the water soluble polymer film composition.

In one embodiment, the water soluble polymer film composition contains from 0.5% to 30% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains from 1% to 20% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 2 to 14% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 4 to 12% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition. In one embodiment, the water soluble polymer film composition contains 4%, 5%, 6%, 7%, 8%, 9% or 10% by weight glycerol as a proportion of the total weight of the water soluble polymer film composition.

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof. In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising glycerol.

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting essentially of glycerol.

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting of glycerol.

(a) poly(vinyl alcohol); and

(b) a plasticiser, which is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

(a) poly(vinyl alcohol); and

(b) a plasticiser, comprising glycerol.

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting essentially of glycerol.

(a) poly(vinyl alcohol); and

(b) a plasticiser, consisting of glycerol. In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol);

(c) water.

(a) poly(vinyl alcohol);

(b) a plasticiser, comprising glycerol; and

(c) water.

(a) poly(vinyl alcohol);

(b) a plasticiser, consisting essentially of glycerol; and

(c) water.

(a) poly(vinyl alcohol);

(b) a plasticiser, consisting of glycerol; and

(c) water.

(a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the water soluble polymer film composition; and

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition.

(a) poly(vinyl alcohol) in an amount of 70 to 98% by weight based on the total weight of the water soluble polymer film composition; and (b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition.

(a) poly(vinyl alcohol) in an amount of 75 to 99% by weight based on the total weight of the water soluble polymer film composition; and

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition.

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

(a) poly(vinyl alcohol) in an amount of 70 to 98% by weight based on the total weight of the water soluble polymer film composition; and

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol.

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol.

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol.

(a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the water soluble polymer film composition;

(b) a plasticiser, in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 0.5 to 30% by weight based on the total weight of the composition. In one embodiment, there is provided a water soluble polymer film composition comprising:

(a) poly(vinyl alcohol) in an amount of 70 to 98% by weight based on the total weight of the water soluble polymer film composition;

(b) a plasticiser, in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition.

(a) poly(vinyl alcohol) in an amount of 75 to 99% by weight based on the total weight of the water soluble polymer film composition;

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition.

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition. In one embodiment, there is provided a water soluble polymer film composition comprising:

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition; and

(c) water in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition.

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition; and

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition; and

In one embodiment, there is provided a water soluble polymer film composition comprising: (a) poly(vinyl alcohol) in an amount of 50 to 99% by weight based on the total weight of the water soluble polymer film composition;

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 0.5 to 30% by weight based on the total weight of the composition.

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof; and

(c) water in an amount of 2 to 14% by weight based on the total weight of the composition.

(b) a plasticiser in an amount of 0.5 to 30% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol; and

(b) a plasticiser in an amount of 2 to 14% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol; and

(b) a plasticiser in an amount of 4 to 12% by weight based on the total weight of the water soluble polymer film composition, wherein the plasticiser is glycerol; and

The film may comprise a single layer or multiple layers. In one embodiment, there is provided a film comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,

19 or 20 layers. Preferably the film comprises 1 to 10 layers, more preferably 1 to 5 layers, more preferably 1, 2 or 3 layers and most preferably 2 layers.

In one embodiment, two or more materials may be extruded simultaneously through a single die. The orifices in the die are arranged such that the layers merge together before cooling. This process saves time because it extrudes two or more layers at the same time, and it provides a method with fewer steps to produce multilayer films. The production rate for a coextruded multilayer film of three layers is typically about 65m/min, and the production rate for a single layer of blown film is typically about 130m/min. Thus, in order to produce 10000m of a three layer multilayer film, it would take almost 4 hours using a single layer blown film process, but only 2½ hours using the coextrusion process.

The thickness of each layer of the film may vary depending on the intended product and the plant-based material to which it is intended to be laminated. In one embodiment, the thickness of each layer is from 1 pm to 0.5 mm. In one embodiment, the thickness of each layer is from 5 pm to 0.1 mm.

The total thickness of the film may vary depending on the intended product and the plant-based material to which it is intended to be laminated. In one embodiment, the thickness of each layer is from 1 pm to 500 pm. In one embodiment, the thickness of each layer is from 2 pm to 2540 pm. In one embodiment, the thickness of each layer is from 5 pm to 200 pm. The water-soluble polymer film may be transparent or opaque. Preferably the water- soluble polymer film is transparent.

Laminated Product The invention also provides laminated products in which one or more layers of the water-soluble polymer film as described herein is fully or partially laminated to one or more layers of a plant-based fibre sheet material such as paper or card. As indicated herein, such a laminated product has the advantages of being both suitable as a packaging material and can be easily processed after use by simply applying water to the laminated product to dissolve the water-soluble polymer layer, thereby allowing the plant-based fibre sheet material to be recycled.

Therefore, according to a further aspect of the present invention there is provided a laminated product comprising: (a) one or more layers of plant-based fibre sheet material, having fully or partially laminated thereto

(b) one or more layers of water-soluble polymer in the form of a film.

According to a further aspect of the present invention there is provided a laminated product comprising:

(b) one or more layers of water-soluble polymer.

According to a further aspect of the present invention there is provided a laminated product consisting essentially of:

(b) one or more layers of water-soluble polymer in the form of a film.

(b) one or more layers of water-soluble polymer.

According to a further aspect of the present invention there is provided a laminated product consisting of:

(b) one or more layers of water-soluble polymer in the form of a film.

(b) one or more layers of water-soluble polymer.

In one embodiment, there is provided a laminated product comprising:

(a) one or more layers of plant-based fibre sheet material, having fully or partially adhered thereto

(b) one or more layers of water-soluble polymer.

In one embodiment, there is provided a laminated product comprising:

(b) one or more layers of water-soluble polymer in the form of a film. In one embodiment, there is provided a laminated product consisting essentially of:

(b) one or more layers of water-soluble polymer.

In one embodiment, there is provided a laminated product consisting essentially of:

(b) one or more layers of water-soluble polymer in the form of a film.

In one embodiment, there is provided a laminated product consisting of:

(b) one or more layers of water-soluble polymer.

In one embodiment, there is provided a laminated product consisting of:

(b) one or more layers of water-soluble polymer in the form of a film.

In one embodiment, the laminated product does not contain a non-water-soluble polymer. In one embodiment, the laminated product does not contain a non-water- soluble synthetic organic polymer. In one embodiment, the laminated product does not contain a thermoplastic synthetic resin. In one embodiment, the laminated product does not contain a polyolefin. In one embodiment, the laminated product does not contain polyethylene.

In one embodiment, the laminated product does not have one or more additional layers of a non-water-soluble polymer. In one embodiment, the laminated product does not have one or more additional layers of a non-water-soluble synthetic organic polymer. In one embodiment, the laminated product does not have one or more additional layers of a thermoplastic synthetic resin. In one embodiment, the laminated product does not have one or more additional layers of a polyolefin. In one embodiment, the laminated product does not have one or more additional layers of polyethylene. In one embodiment, the layer of water-soluble polymer is present on only one side of the layer of plant-based fibre sheet material. In one embodiment, a layer of water- soluble polymer is present on both sides of the layer of plant-based fibre sheet material. In one embodiment, a layer of plant-based fibre sheet material is present on both sides of the layer of water-soluble polymer.

In one embodiment, there is provided a laminated product according to the invention comprising, consisting essentially of or consisting of a layer of water-soluble polymer adhered to a layer of plant-based fibre sheet material via one or more (typically only one or two) intermediate adhesive layers.

In one embodiment, there is provided a laminated product according to the invention comprising, consisting essentially of or consisting of a layer of water-soluble polymer film adhered to a layer of plant-based fibre sheet material via one or more (typically only one or two) intermediate adhesive layers.

The water-soluble polymer film may typically be the water-soluble polymer film according to the invention as described above. In one embodiment, the water- soluble polymer is poly(vinyl alcohol) (PVOH). The poly(vinyl alcohol) may be as defined and exemplified above, either in its broadest aspect or a preferred aspect.

In each of the above embodiments of the laminated product, the water-soluble polymer (which typically forms the film) is the sole component of the water-soluble polymer layer. In another embodiment of the laminated product, the water-soluble polymer which typically forms the film, typically poly(vinyl alcohol), is present as part of a composition as defined above, either in its broadest aspect or any of the preferred aspects.

In one embodiment of the laminated product, the composition used to form the water- soluble polymer film contains a plasticiser. As described herein, it has surprisingly been found according to the present invention that the inclusion of a plasticiser in the water-soluble polymer composition serves to strengthen the film which forms part of the laminated product. In particular, the inclusion of a plasticiser renders the film layer of the laminated product resistant to degradation when exposed to light and/or inadvertent wetting such as rainwater, but the laminated product can still be recycled by separating the water-soluble polymer layer from the plant-based fibre sheet layer by the application of water in typical repulping conditions. In any the above embodiments of the laminated product, the plasticiser may be any of those defined and exemplified above, either in its broadest aspect of a preferred aspect, in relation to the composition used to form the film. It is particularly preferred that the plasticiser is glycerol.

In each of the above embodiments of the laminated product, the amounts by weight of the poly(vinyl alcohol); the plasticiser; and, if present, water, in the water-soluble polymer (typically the film) are as defined and exemplified above, either in its broadest aspect of a preferred aspect, in relation to the composition used to form the film.

The plant-based fibre sheet material may be any plant-based fibre sheet material typically known in the art. In this specification the term “fibre” when used alone takes its normal meaning in the art of a substance that is significantly longer than it is wide. Plant-based fibres are available from a wide variety of plant materials: examples of such fibres include wood fibres, wheat straw and sugar cane / bagasse.

The fibre from which the sheet material is made is plant-based. In one embodiment the sheet material is made from a single type of plant-based fibre. In one embodiment the sheet material is made from a mixture of plant-based fibres.

As is known to the person skilled in the art, plant-based fibres are typically more environmentally sustainable than those from some synthetic organic polymers, particularly polyolefins: once the water-soluble polymer has been removed, they can typically be recycled as paper material where systems allow, or can be composted.

Typical chemical components of plant-based fibres include cellulose, hemicellulose, and lignin. In one embodiment, the fibres contain cellulose. In one embodiment, the fibres contain hemicellulose. In one embodiment, the fibres contain lignin.

In one embodiment, the plant-based fibre sheet material is paper. In this specification the term “paper” means a thin sheet material produced by mechanically and/or chemically processing cellulose fibres, typically derived from wood, rags, grasses or other vegetable sources. As is known to the person skilled in the art, the process typically involves the application of water to the fibres, draining the water through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying.

Paper is commercially available from a wide variety of sources, in a wide range of grades, sizes and thicknesses, and all types of paper are applicable to the laminated product of the present invention. Papers suitable for flexo/gravure printing with lamination are particularly suitable for the laminated product.

In one embodiment, the plant-based fibre sheet material is card (or cardboard). As is known to the person skilled in the art, card is made from cellulose fibres, typically derived from wood, rags, grasses or other vegetable sources, in a similar manner to paper. Card is generally known to be thicker more rigid and heavier than paper, and may typically (although not exclusively) made up of multiple layers.

The laminated product may comprise a single layer of each type of material (i.e. the water-soluble polymer and of the plant-based fibre sheet material) multiple layers of either or both types of material. In one embodiment, the laminated product may have

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 layers of the plant- based fibre sheet material. In one embodiment, the laminated product may have 1,

2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 layers of the water- soluble polymer film.

The thickness of the water-soluble polymer film layer (or each layer, if multiple layers are present) of the laminated product may vary depending on the intended use. In one embodiment, the thickness of the or each water-soluble polymer film layer is from 1 pm to 5 mm. In one embodiment, the thickness of the or each water-soluble polymer film layer is from 2 pm to 2 mm. In one embodiment, the thickness of the or each water-soluble polymer film layer is from 5 pm to 1 mm. In one embodiment, the thickness of the or each water-soluble polymer film layer is from 10 pm to 0.5 mm. In one embodiment, the thickness of the or each water-soluble polymer film layer is from 20 pm to 0.2 mm.

Similarly, the thickness of the plant-based fibre sheet material layer (or each layer, if multiple layers are present) of the laminated product may vary depending on the intended use. In one embodiment, the thickness of the or each plant-based fibre sheet material is from 1 pm to 5 mm. In one embodiment, the thickness of the or each plant-based fibre sheet material layer from 2 pm to 2 mm. In one embodiment, the thickness of the or each plant-based fibre sheet material layer is from 5 pm to 1 mm. In one embodiment, the thickness of the or each plant-based fibre sheet material layer is from 10 pm to 0.5 mm. In one embodiment, the thickness of the or each plant-based fibre sheet material layer is from 20 pm to 0.2 mm.

When the plant-based fibre material is paper, in one embodiment the weight of the paper per unit area may range from 50 grams per square metre (gsm) to 500 gsm.

In one embodiment the weight of the paper per unit area may range from 20 gsm to 200 gsm. In one embodiment the weight of the paper per unit area may range from 30 gsm to 150 gsm. In one embodiment the weight of the paper per unit area may range from 50 gsm to 100 gsm. In one embodiment the weight of the paper per unit area may range from 40 gsm to 80 gsm. In one embodiment the weight of the paper per unit area may range from 90 gsm to 300gsm. When the plant-based fibre material is cardboard, in one embodiment the weight of the cardboard per unit area may range from 250gsm to 5550 gsm. In one embodiment the weight of the cardboard per unit area may range from 200gsm to 400 gsm.

In one embodiment of the laminated product of the invention, the whole of a layer or layers of the plant-based fibre sheet material is laminated to the whole of a layer or layers of the water-soluble polymer film, so that the resultant product has entire layers of both types of product.

In one embodiment of the laminated product of the invention, the whole of a layer or layers of the plant-based fibre sheet material is adhered to the whole of a layer or layers of the water-soluble polymer film, so that the resultant product has entire layers of both types of product.

In another embodiment of the laminated product of the invention, part of a layer or layers of the water-soluble polymer film is laminated to the whole of a layer or layers of plant-based fibre sheet material.

In another embodiment of the laminated product of the invention, part of a layer or layers of the water-soluble polymer film is adhered to the whole of a layer or layers of plant-based fibre sheet material.

In another embodiment of the laminated product of the invention, part of a layer or layers of the plant-based fibre sheet material is laminated to the whole of a layer or layers of the water-soluble polymer film. In another embodiment of the laminated product of the invention, part of a layer or layers of the plant-based fibre sheet material is adhered to the whole of a layer or layers of the water-soluble polymer film.

In one embodiment of the laminated product of the invention, the layer or layers of the water-soluble polymer film is applied to the layer or layers of the plant-based fibre sheet material by means of a heat seal. In this specification the term “heat seal” means the application of heat and/or pressure to allow the layers to be bonded together. Typically, the heat sealing is carried out at a temperature of 100 to 250°C, preferably 135 to 200°C. Typically, the heat sealing is carried out at a pressure of 1.5 to 4 bar, preferably 2 to 3 bar.

In one embodiment, the heat seal is a fin seal. As is known to the person skilled in the art, in a fin seal, both interior edges of the film are sealed together and the fin is folded over. In one embodiment, the heat seal is a lap seal. As is known to the person skilled in the art, in a lap seal, the exterior of the film is sealed onto the interior of the film. In one embodiment, the heat seal is a transverse seal. As is known to the person skilled in the art, in transverse sealing, or cross sealing, the packaging materials are sealed in a transverse direction, which is perpendicular to the direction in which the packaging material is conveyed. In one embodiment, the heat seal is a longitudinal seal. As is known to the person skilled in the art, in this type of sealing, the sealed edge will be parallel to the direction of the film movement.

Examples of sealing methods and types typically used in food packaging are described in llhan et al. Packag Techno! Sci. 2021, 34, 321-337.

In another embodiment of the invention, there is provided a laminated product comprising: one or more layers of plant-based fibre sheet material, having one or more adhesive layer applied to only one side thereof; and, one or more layers of water-soluble polymer film adhered to the one or more layers of the plant-based fibre sheet material by means of the one or more adhesive layers.

In another embodiment of the invention, there is provided a laminated product consisting essentially of: one or more layers of plant-based fibre sheet material, having one or more adhesive layer applied to only one side thereof; and, one or more layers of water-soluble polymer film adhered to the one or more layers of the plant-based fibre sheet material by means of the one or more adhesive layers.

In another embodiment of the invention, there is provided a laminated product consisting of: one or more layers of plant-based fibre sheet material, having one or more adhesive layer applied to only one side thereof; and one or more layers of water-soluble polymer film adhered to the one or more layers of the plant-based fibre sheet material by means of the one or more adhesive layers.

In another embodiment of the invention, there is provided a laminated product of the invention comprising: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied thereto; one or more layers of a second adhesive applied to the first adhesive layer; and, one or more layers of plant-based fibre sheet material applied to the one or more layers of the second adhesive.

In another embodiment of the invention, there is provided a laminated product of the invention comprising: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied to only one side thereof; one or more layers of a second adhesive applied to the first adhesive layer; and one or more layers of water-soluble polymer film applied to the one or more layers of the second adhesive.

In another embodiment of the invention, there is provided a laminated product of the invention comprising: one or more layers of water-soluble polymer film, having one or more layers of a first adhesive applied thereto; one or more layers of a second adhesive applied to the first adhesive layer; and one or more layers of plant-based fibre sheet material applied to the one or more layers of the second adhesive. In another embodiment of the invention, there is provided a laminated product of the invention comprising: one or more layers of water-soluble polymer film, having one or more layers of a first adhesive applied to only one side thereof; one or more layers of second adhesive applied to the first adhesive layer; and one or more layers of plant-based fibre sheet material applied to the one or more layers of the second adhesive.

In the above embodiment containing a first and a second adhesive layer, the first adhesive layer is typically an adhesive capable of being applied to the water-soluble polymer film using pressure alone, and the second adhesive layer is typically an adhesive capable of being applied to the first adhesive layer using heat and pressure.

In another embodiment of the laminated product of the invention, the layer or layers of the plant-based fibre sheet material is provided with an aperture which is wholly or partially covered by a layer or layers of the water-soluble polymer film adhered thereto. This is of particular value when the laminated product is used for packaging, as it enables the customer to see the product enclosed by the packaging through the while ensuring that the product is fully recyclable as indicated above.

The laminated product according to the present invention may take any physical form known in the art. In one embodiment, the laminated product is provided in the form of a sheet. In one embodiment, the laminated product is provided in the form of a roll.

Adhesive

The laminated product according to the invention may comprise, consist essentially of, or consist of, one or more (typically only one) layers of water-soluble polymer (typically a film) adhered to one or more (typically only one) layers of plant-based fibre sheet material via one or more (typically one or two) intermediate adhesive layers. A wide range of adhesives are commercially available, and examples of adhesives are well known to those skilled in the art. In one embodiment, the adhesive is solvent-based. In one embodiment, the adhesive is solventless.

In one embodiment, the adhesive does not contain, consist essentially of, or consist of poly(vinyl alcohol). Without wishing to be bound by theory, it has been found that poly(vinyl alcohol)-based adhesives are not washed away from the paper layer during the repulping process, and therefore their use is preferably avoided according to the present invention.

In one embodiment, the adhesive does not contain, consist essentially of, or consist of poly(vinyl acetate).

In one embodiment, the adhesive does not contain, consist essentially of, or consist of, a water-soluble adhesive. In one embodiment, the adhesive is not water-soluble. Without wishing to be bound by theory, it has been found that the use of water- soluble adhesives in the laminated products of the present invention can result in disintegration of the product during use or prior to recycling, leaving traces of contaminants present on the plant-based fibre sheet material.

In one embodiment, the adhesive layer is one of the LOCTITE® range of adhesives commercially available from Henkel. In one embodiment, the adhesive is the LOCTITE® LIOFOL HS 2809-22 RE adhesive commercially available from Henkel.

One particular example of a laminated product according to the invention is shown in Fig. 2. The product is generally shown at 50 and comprises a layer of water-soluble polymer (typically PVOH) 52 adhered to a layer of plant-based fibre sheet material (typically paper or cardboard) 56 via an adhesive layer 54. The product typically consists of the layer of water-soluble polymer film 52, to one side of which is applied the adhesive layer 54. The plant-based fibre sheet material 56 may then be applied such that the adhesive layer 54 adheres to the plant-based fibre sheet material 56.

A further example of a laminated product according to the invention is shown in Fig. 2A. The product is generally shown at 60 and has a layer of plant-based fibre sheet material (typically paper or cardboard) 66, to one side of which is applied the adhesive layer 64, typically by dry bond heat and/or pressure sealing. The water- soluble polymer 62 is then applied (typically via wet coating and lamination) such that it adheres to the side of the plant-based fibre sheet material bearing the adhesive layer 64.

A yet further example of a laminated product according to the invention is shown in Fig. 2B. The product is generally shown at 70 and has a layer of plant-based fibre sheet material (typically paper or cardboard) 78, to one side of which is applied a first adhesive layer 76, typically by dry bond heat and/or pressure sealing. To this first adhesive layer is applied a second adhesive layer 74, typically by cold seal coating. The water-soluble polymer layer (typically PVOH) 72 is then applied such that the second adhesive layer 74 so it adheres thereto.

Metal Laver

In one embodiment, the laminated product includes a metal layer. The metal layer may comprise a single metal or a mixture of metals (i.e. an alloy). In one embodiment, the metal layer comprises a single metal. In another embodiment, the metal layer comprises a mixture of 2, 3, 4, 5, 6, 7, 8, 9 or 10 metals.

In one embodiment, the metal layer comprises one or more metals capable of passivation, typically by forming an oxide layer on the surface thereof. Examples of metals capable of forming a passivation oxide layer include aluminium, beryllium, chromium, titanium, and zinc. In one embodiment, the metal comprises, consists essentially of, or consists of aluminium. In one embodiment, the metal comprises, consists essentially of, or consists of titanium.

The metal layer may be passivated, in that an oxide layer is formed on the surface thereof. Examples of passivation oxide layers include aluminium oxide, beryllium oxide, chromium oxide, titanium oxide, and zinc oxide. In one embodiment, the passivated metal layer comprises, consists essentially of, or consists of aluminium oxide. In one embodiment, the passivated metal layer comprises, consists essentially of, or consists of titanium oxide.

Therefore, in one embodiment of the invention, there is provided a laminated product comprising, consisting essentially of or consisting of: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied thereto; one or more metal layers applied to the one or more first adhesive layers, the metal layers optionally being passivated; one or more layers of a second adhesive applied to the one or more metal layers; and one or more layers of water-soluble polymer film adhered to the one or more metal layers via the one or more layers of the second adhesive.

In another embodiment of the invention, there is provided a laminated product comprising, consisting essentially of or consisting of: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied to only one side thereof; one or more metal layers applied to the one or more adhesive layers, the metal layers optionally being passivated; one or more layers of a second adhesive applied to the one or more metal layers; and one or more layers of water-soluble polymer film adhered to the one or more metal layers via the one or more layers of the second adhesive.

The metal layer typically comprises microparticles and/or nanoparticles of the metal. In one embodiment, the particle size of the metal is between 100 nm and 500 pm. In one embodiment, the particle size of the metal is between 1 pm and 100 pm. In one embodiment, the particle size of the metal is between 10 pm and 50 pm. In one embodiment, the particle size of the metal is between 20 pm and 30 pm.

Without wishing to be bound by theory, it is believed that the inclusion of the metal layer provides a barrier which protects the laminated product from accidental exposure to water (such as rainwater), while still allowing the water-soluble polymer layer to be removed under typical conditions of the repulping process.

An example of a laminated product according to the invention including a metal layer is shown in Fig. 2C. The product is generally shown at 80 and has a layer of plant- based fibre sheet material (typically paper or cardboard) 82, to one side of which is applied a first adhesive layer 84, typically by dry bond heat and/or pressure sealing. The metal layer 86 is then applied to the first adhesive layer, typically by physical vapour deposition as defined and exemplified below. A second adhesive layer 87 is then applied to the other side of the metal layer. The water-soluble polymer layer 88 is then applied to the second adhesive layer 87 such that the second adhesive and metal layers adhere thereto.

Container

In one embodiment, the laminated product of the invention takes the form of a container. In such a product, at least the plant-based fibre (typically paper or card, preferably card) layer or layers are formed into a structure which is capable of containing a product.

Therefore, in a further aspect of the invention, there is provided a container having:

(b) a layer of water-soluble polymer in the form of a film.

In a further aspect of the invention, there is provided a container having:

(b) a layer of water-soluble polymer.

(b) a layer of water-soluble polymer in the form of a film, wherein the film does not contain amylose.

The size of the container may vary depending on the nature and amount of materials it is intended to contain.

The general shape of the container may be any known to those skilled in the art. Examples of typical shapes include cylindrical, ovoid, spherical, cuboid, and prismatic (including triangular, rectangular and hexagonal prismatic).

The container may take any form generally known in the art, provided that it creates a partially or fully enclosed space that can be used to contain, store, and/or transport objects or materials. Examples of forms of containers generally known in the art include flexible containers such as bags, packets and wallets, and rigid containers such as bottles, jars, barrels, cans, drums, tubs and boxes.

In one embodiment, the container is a bag (or sack). As is known to the person skilled in the art, bags are flexible containers having an opening at the top, typically used for carrying materials. Therefore, in one embodiment, there is provided a bag having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer. The bag may be provided with one or more handles to aid carrying.

In one embodiment, the container is a packet. As is known to the person skilled in the art, a packet is a container which is typically made from flexible material, and is typically used for containing materials. Therefore, in one embodiment, there is provided a packet having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer. The packet is typically provided to the consumer in a sealed manner. The packet may be provided with one or more means to aid opening, such as rip or tear lines.

In one embodiment, the container is a wallet. As is known to the person skilled in the art, a wallet is a flat container which is typically used for containing small personal items such as paper currency, cards and documents. Therefore, in one embodiment, there is provided a wallet having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer. The wallet is typically provided with receptacles to shore such items.

In one embodiment, the container is a box. As is known to the person skilled in the art, a box is a container which is typically rigid and with a regular shape which may be used for containing a wide variety of items. Therefore, in one embodiment, there is provided a box having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer. The general shape of the box may vary depending on the application: it may typically have a rectangular cross-section, but other shapes such as cuboid, cylindrical, spherical and oval may be envisaged by those skilled in the art.

In one embodiment, the container is a bottle. As is known to the person skilled in the art, bottles are containers typically made to transport liquids and typically have a narrow neck and a mouth sealable by a sealing means. Therefore, in one embodiment, there is provided a bottle having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer.

In one embodiment, the container is a jar. As is known to the person skilled in the art, jar are containers typically made to transport liquids and typically have a wider opening sealable by a sealing means. Therefore, in one embodiment, there is provided a jar having a structure of plant-based fibre sheet material, having fully or partially laminated thereto a layer of water-soluble polymer.

The container may be produced by any means known to those skilled in the art of manufacturing containers. In one embodiment, the container may be made from a sheet of plant-based fibre material by first cutting the sheet to the desired dimensions of the eventual container and then folding the cut sheet to so it is assembled into the container. This is typically advantageous when the container is made of foldable plant-based fibre material such as paper or cardboard.

The plant-based fibre sheet material may be any plant-based fibre sheet material typically known in the art.

In one embodiment, the structure may be provided with an aperture which is wholly or partially covered by a layer or layers of the water-soluble polymer film which is adhered thereto. This is of particular value when the container is used for packaging, as it enables the customer to see the product enclosed by the packaging through the while ensuring that the container is fully recyclable as indicated above.

In one embodiment, the structure may be provided with an aperture which is wholly or partially covered by a layer or layers of the water-soluble polymer film which is adhered thereto. This is of particular value when the container is used for packaging, as it enables the customer to see the product enclosed by the packaging through the while ensuring that the container is fully recyclable as indicated above. Therefore, in one embodiment, there is provided a container having a structure of plant-based fibre sheet material, the container having an aperture which is fully or partially covered by a layer of water-soluble polymer laminated to the structure surrounding the aperture.

In one embodiment, there is provided a box having a structure of plant-based fibre sheet material, the box having an aperture which is fully or partially covered by a layer of water-soluble polymer laminated to the structure surrounding the aperture.

In one embodiment, there is provided a bag having a structure of plant-based fibre sheet material, the bag having an aperture which is fully or partially covered by a layer of water-soluble polymer laminated to the structure surrounding the aperture.

In one embodiment, there is provided a packet having a structure of plant-based fibre sheet material, the packet having an aperture which is fully or partially covered by a layer of water-soluble polymer laminated to the structure surrounding the aperture.

One particular example of such a container is the box shown in perspective view in Fig. 3 and which is typically used for containing prepared foodstuffs such as cut sandwiches. The container is generally shown at 100 and is made of plant-based fibre material such as card. The particular container shown is triangular in cross- section, and comprises two triangular side walls 101a, 101b, end walls (not visible) and a diagonal wall 102 from which outwardly extend flanges 103a, 103b to allow for easy picking up and opening. The diagonal wall 102 is provided with an aperture 104 which is covered by a layer of clear water-soluble polymer material, for example poly(vinyl alcohol), which is laminated to the area surrounding the aperture. The layer of water-soluble polymer allows the contents to be viewed, while being removable by treatment with water on disposal to enable the plant-based fibre (e.g. card) to be recycled.

Method of Producing Laminated Product

The invention also provides a method of producing the laminated product. These methods are applicable to all types of the laminated product of the present invention, including the sheet material and when it takes the form of a more structured material such as a container. Therefore, there is provided a method of producing the laminated product of the invention, the method comprising:

(i) providing a plant-based fibre sheet material layer; and

(ii) applying the water-soluble polymer layer such that it fully or partially laminates to the plant-based fibre sheet material layer.

Typically, the water-soluble polymer layer is adhered to the plant-based fibre sheet material layer using an adhesive. A wide range of adhesives are commercially available, and examples of adhesives are well known to those skilled in the art.

In one embodiment, the adhesive is a poly(vinyl acetate)-based adhesive. Poly(vinyl acetate)-based adhesives are particularly advantageous in the present invention as they enable poly(vinyl alcohol) to be bound while retaining its water solubility. Examples of poly(vinyl acetate)-based adhesives include the POVAL™ series of adhesives available from Kuraray.

In one embodiment, the adhesive is solvent-based. In one embodiment, the adhesive is solventless.

In one embodiment, the adhesive is the LOCTITE® LIOFOL HS 2809-22 RE adhesive commercially available from Henkel.

In one embodiment, in a first step the adhesive is applied to one side of the plant- based fibre sheet layer. Typically this is carried out by coating that side of the plant- based fibre sheet layer using an adhesive in the form of a liquid. The liquid adhesive may then be allowed to dry. In one embodiment, the adhesive is then cured, typically by the application of ultraviolet radiation. The adhesive-bearing surface of the plant- based fibre sheet material is then dry but tacky, such that the water-soluble polymer layer or, if included, the metal layer, may bond thereto.

In one embodiment, in a subsequent step the plant-based fibre sheet layer bearing the adhesive is then applied to the water-soluble polymer layer. Typically this step is carried out using the application of heat and/or pressure. When heat is applied, typically, this step is carried out at a temperature of 100 to 250°C, preferably 135 to 200°C. Typically, this step is carried out at a pressure of 1.5 to 4 bar, preferably 2 to 3 bar.

In one embodiment the step of applying the adhesive is carried out using pressure alone. Typically, this is carried out at a pressure of 5 to 50 bar, preferably 5 to 20 bar.

In one embodiment, there is provided a method of producing the laminated product of the present invention, the method comprising the following steps:

(a) applying an adhesive to one side of a plant-based fibre sheet layer; and

(b) applying the plant-based fibre sheet layer bearing the adhesive to the water- soluble polymer layer, using the application of heat and/or pressure.

It has been surprisingly found by the present inventors that producing the laminated product of the present invention according to the above method results in a product where the water-soluble polymer layer remains firmly bonded to the plant-based fibre sheet layer during use, but can still be separated during the recycling process by applying water to the laminated product, causing the water-soluble polymer layer to dissolve. This confers considerable advantages over prior art laminated products of this type, as no contaminants remain attached to the plant-based fibre sheet layer enabling it to be easily recycled or repulped.

In one embodiment, the water-soluble polymer layer is applied to the plant-based fibre sheet material layer using the application of heat and/or pressure. In one embodiment, the water-soluble polymer layer is applied directly to the plant-based fibre sheet material layer using the application of heat and/or pressure.

A preferred lamination process is shown in Fig. 4 and involves a lamination machine shown generally at 200. The plant-based fibre sheet material (e.g. paper) may be applied via unit 202 to an unwinder 204 of the lamination machine, which in one particular example is configured for use with solventless adhesives. The plant-based fibre sheet material is then passed through rolls 210, 212 and has hot glue (in one particular example, poly(vinyl acetate)-based glue) applied thereto in unit 220 comprising dosing unit 222 and application rolls 224, 226. The glued plant-based fibre sheet material can then be passed via rolls 230, 232 into drying tunnel 234.

Separately, the water-soluble polymer film can be applied via unit 206 to a second unwinder 208, and then passes via rolls into laminator unit 250, in which the glued paper and the water-soluble polymer film can be pressed together between rolls 252, 254 to form the laminated product. The final product can then be passed via rolls 256, 258 and reeled onto winder 262. The laminate can then be cured in controlled conditions inside storage.

In another embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of water-soluble polymer film, applying one or more (typically only one or two) adhesive layers to the water-soluble polymer film; and applying one or more layers of plant-based fibre sheet material to the adhesive layer such that it adheres thereto.

In another embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of water-soluble polymer film, applying one or more (typically only one or two) adhesive layers to only one side of the water-soluble polymer film; and applying one or more layers of plant-based fibre sheet material to the adhesive layer such that it adheres thereto.

In another embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more (typically only one or two) adhesive layers to the plant-based fibre sheet material; and applying one or more layers of water-soluble polymer film to the adhesive layer such that it adheres thereto.

In another embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more (typically only one or two) adhesive layers to only one side of the plant-based fibre sheet material; and applying one or more layers of water-soluble polymer film to the adhesive layer such that it adheres thereto.

In the above embodiment, the adhesive layer is typically applied to the one or more layers of plant-based fibre sheet material by the application of heat and/or pressure, typically dry bond heat and/or pressure sealing. As is known to the person skilled in the art, typically this process comprises coating one side of the plant-based fibre sheet layer using an adhesive layer in the form of a liquid. The liquid adhesive is then allowed to dry. In one embodiment, the adhesive is dried by curing, typically by the application of ultraviolet radiation. The water-soluble polymer film layer or, if included, the metal layer can then be applied to the adhesive layer using heat and pressure, or pressure alone.

In another embodiment of the invention, there is provided a method of producing the laminated product of the invention comprising: providing one or more layers of plant-based fibre sheet material, applying one or more layers of a first adhesive to only one side of the plant-based fibre sheet material; applying one or more layers of a second adhesive to the one or more layers of the first adhesive; and applying one or more layers of water-soluble polymer film to the one or more layers of the second adhesive.

In the above embodiment, the one or more layers of the first adhesive layer are typically applied to the one or more layers of plant-based fibre sheet material by the application of heat and pressure. Typically, one side of the plant-based fibre sheet layer is coated with the first adhesive layer in the form of a liquid. The liquid adhesive is then allowed to dry. In one embodiment, the adhesive is dried by curing, typically by the application of ultraviolet radiation.

Typically, the first adhesive layer is applied at a temperature of 100 to 250°C, preferably 135 to 200°C. Typically, the first adhesive layer is applied at a pressure of 1.5 to 4 bar, preferably 2 to 3 bar.

In the above embodiment, the one or more layers of the second adhesive are typically applied to the one or more layers of the first adhesive by the application of heat and pressure. Typically, one side of the plant-based fibre sheet layer is coated with the first adhesive layer in the form of a liquid. The liquid adhesive is then allowed to dry. In one embodiment, the adhesive is dried by curing, typically by the application of ultraviolet radiation. Typically, this step is carried out at a temperature of 100 to 250°C, preferably 135 to 200°C. Typically, this step is carried out at a pressure of 1.5 to 4 bar, preferably 2 to 3 bar.

In the above embodiment, the water-soluble polymer film is typically applied to the second adhesive layer by the application of pressure alone to enable the second adhesive layer to adhere to the plant-based fibre sheet material. Typically, this step is carried out at a pressure of 5 to 50 bar, preferably 5 to 10 bar.

When the laminated product of the present invention contains a metal layer (as defined and exemplified above, either in its broadest aspect or a preferred aspect), the method of producing it typically comprises the first step as indicated above of applying a first adhesive layer to one side of the plant-based fibre sheet layer. In a second step, the metal layer is then applied to the adhesive-bearing side of the plant- based fibre sheet layer. In a third step, a second adhesive layer is applied to the other side of the metal layer. In a fourth step, the water-soluble polymer film layer is then applied to the second adhesive layer.

In one embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more (typically only one or two) layers of a first adhesive to the plant- based fibre sheet material; applying one or more metal layers to the one or more layers of the first adhesive; applying one or more (typically only one or two) layers of a second adhesive to the one or more metal layers; and applying one or more layers of water-soluble polymer film to the one or more layers of the second adhesive such that it adheres thereto.

In one embodiment of the invention, there is provided a method of producing the laminated product of the invention, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more (typically only one or two) layers of a first adhesive to only one side of the plant-based fibre sheet material; applying one or more metal layers to the one or more layers of the first adhesive; applying one or more (typically only one or two) layers of a second adhesive to the one or more metal layers; and applying one or more layers of water-soluble polymer film to the one or more layers of the second adhesive such that it adheres thereto.

Typically, the metal layer is applied via a physical vapour deposition (PVD) method. As is known to the person skilled in the art, PVD methods typically comprise providing a vapour source of the or each component element of the metal layer and depositing the or each elements from the vapour source onto the surface of the layer to which the metal layer is applied, such that a layer of the metal forms on the surface of that layer.

One type of physical vapour deposition method suitable for application of the metal layer is a sputter deposition method. As is known to the person skilled in the art, sputter deposition typically comprises ejecting material from one or more targets that is a source of the or each component element of the metal layer, such that the sputtered atoms of the element form a vapour, and directing the vapour onto the layer to which the metal layer is applied, such that a layer of the metal forms on the surface of that layer.

Therefore, in one embodiment, there is provided the above method of producing a laminated product of the invention including a metal layer, wherein the metal layer is applied via a sputtering deposition method comprising: providing a sputtering target, the sputtering target comprising a source of atoms for constituting the metal layer, and sputtering the targets to form the metal layer on the surface of the layer. The application of the metal layer typically results in the product bearing the metal layer having a positive or negative charge.

Typically, the physical vapour deposition method, for example the sputtering method, is carried out at elevated temperature. The physical vapour deposition method, for example the sputtering method, is typically carried out at a temperature of 40 to 400°C, preferably 60 to 250°C.

Typically, the physical vapour deposition method, for example the sputtering method, is carried out under reduced pressure, such as under vacuum. The physical vapour deposition method, for example the sputtering method, is typically carried out at a pressure of 0.001 to 10 Pa, preferably 0.01 to 1 Pa.

Following the application of the metal layer the plant-based fibre sheet layer bearing the adhesive and the metal layer is then applied to the water-soluble polymer layer. This step is typically carried out, using the application of heat and/or pressure.

Without wishing to be bound by theory, it is believed that the introduction of the metal layer into the laminated products of the present invention can provide a barrier which protects the later from moisture and oxygen in use, but can still be easily removed by the application of water during the repulping process, without leaving traces of metals present on the plant-based fibre sheet material, thus allowing this to be recycled.

There is also provided a method of producing the laminated product of the invention comprising:

(i) providing a plant-based fibre sheet material layer; and

(ii) producing the water-soluble polymer layer by extrusion of the water soluble polymer onto the plant-based fibre sheet material layer such that it laminates directly thereto.

One example of a direct extrusion process is shown in Fig. 5. The apparatus is shown generally at 300 and comprises an extruder 302 having a feed 304 and an outlet 306 which feeds into an elongate die 308, the walls of which converge towards an elongate slit 310. The water-soluble polymer (e.g. PVOH) is fed via feed 304 and is extruded in extruder 304 through before passing through the die 308 to form a film 312 which is urged towards chill roll 314. Separately, a sheet of plant-based fibre sheet material (e.g. paper) 316 is unwound from unwinder 318 and is rolled over nip roll 320 towards chill roll 314.

On the chill roll 314, the two layers are combined to provide a laminated product 326 in which plant-based fibre sheet material is laminated directly to the water-soluble polymer. This is then wound onto winder 328.

Alternatively, in a coextrusion process, two or more extruders are used to melt and deliver two or more different polymers to a single die, which extrude the materials into the desired form. Typical extruder sizes, rotational speeds, and the resulting layer thicknesses of the materials are as described and exemplified above in relation to extrusion of single films.

The temperature at which the lamination is carried out may vary based on the type and grade of the water-soluble polymer, the type and grade of the plant-based fibre sheet material, and the final intended product. In one embodiment, the lamination is carried out at a temperature of room temperature to 100°C. In one embodiment, the lamination is carried out at a temperature of 50 to 80°C. In one embodiment, the lamination is carried out at a temperature of 55 to 65°C.

The pressure at which the lamination is carried out may vary based on the type and grade of the water-soluble polymer, the type and grade of the plant-based fibre sheet material, and the final intended product. In one embodiment, the extrusion is carried out at a pressure of 50 to 500 kPa. In one embodiment, the extrusion is carried out at a pressure of 100 to 300 kPa.

Recycling and Repulpinq

When the laminated product of the present invention has been used, it can be easily recycled. Typically, this can be carried out by mixing the laminated product for recycling with an aqueous medium, typically water, and stirring the mixture to form a suspension of the plant-based fibres from the plant-based fibre sheet material.

During this process, the water-soluble polymer layer of the laminated product dissolves in the aqueous medium, such that only the plant-based fibre sheet material remains suspended.

Typically, the suspension contains a large excess of aqueous medium compared with fibres. Typically, the suspension contains 0.1% to 10% of fibres and 90 to 99.9% water (by weight of the total weight of the suspension), preferably 0.5 to 2% of fibres and 98% to 99.5% water (by weight of the total weight of the suspension).

Typically, the suspension is carried out at 10 to 90°C, preferably 20 to 50°C.

The aqueous medium may then be removed from the suspension in a conventional manner. The suspension of plant-based fibres may then be converted back to plant- based fibre sheet material, such as paper or cardboard, in a conventional manner. Typically this is carried out by sieving, such that the fibres are laid down. Water may further be removed from the fibres by a number of conventional steps such as increased pressure, reduced pressure, and/or heating, to produce a dry sheet of new material.

Examples

Example 1 - Poly (vinyl alcohol) film production

Poly(vinyl alcohol) (pellets of HYDROPOL 33100 series from Aquapak Polymers, UK, having an approximate composition of 80-85% poly(vinyl alcohol), 5-10% glycerol as plasticiser, and 5-10% water, all by weight of the total weight of the composition) was preheated to 40°C and then was placed into dosing systems. Fixed amounts of between 50 and 100 pellets were transferred through these dosing systems to 5 extruders, inside which the pellets are molten at between 180 to 240 °C. The molten pellets were pressurized to a pressure exceeding 27 MPa by rotating screws rotating at 50 to 100 rpm, and the molten poly(vinyl alcohol) was passed through a die. After passing through the die, the poly(vinyl alcohol) was cooled by a cooling air ring system which simultaneously introduced air into the system to form a bubble which was supported by a stabilizing cage. This bubble was then collapsed using a collapsing frame and nip rolls to produce a film of transparent poly(vinyl alcohol) that was can be cut and then wound onto a reel.

Example 2 - Lamination

A lamination process was carried out using the procedure generally shown in Fig. 4 using a lamination machine (Nordmeccanica Suplex Combi, available from Nordmeccanica Group). Gravure printed paper (Nika Flex) was preconditioned in storage and applied via unit 202 to unwinder 204 of the lamination machine configured for use with solventless adhesives. The paper passed through rolls 210, 212 and has hot glue, typically poly(vinyl acetate)-based glue, applied thereto in unit 220 comprising dosing unit 222 and application rolls 224, 226. The glued paper than passes via rolls 230, 232 into drying tunnel 234.

Separately, poly(vinyl alcohol) film produced according to example 1 was applied via unit 206 to a second unwinder 208, and then passes via rolls into laminator unit 250, in which the glued paper and the poly(vinyl alcohol) film are pressed together between rolls 252, 254 to form the laminated product. The final product is passed via rolls 256, 258 and reeled on winder 262. The laminate was then cured in controlled conditions inside storage.

Example 3 - Application of Metal Laver by Vapour Deposition

A PVD process is shown in outline in Fig. 6, generally at 350. Solid metal wire 352 is provided and is evaporated in an evaporation step 354 to produce a vapour 356.

The vapour is then transported and deposited on the target substrate in a subsequent step 358 to produce a solid layer of metal 360.

Figure 7 shows generally at 400 an example of a vacuum chamber suitable for carrying out a sputtering process for application of the metal layer. The paper layer 402 bearing a first adhesive layer is introduced into the chamber. Separately, a sputtering gas 404 (such as argon) is separately introduced into the chamber, such that ions of the gas 406 are applied to a sputtering target of the desired metal 408 (aluminium byway of example). The metal 408 is present on a holding plate 414 of the target material. Sputtered metal atoms 410 are then deposited as a layer 412 on the paper layer bearing the first adhesive layer. A source of electric charge 416 applies a positive or negative charge to the film as it runs through the vacuum chamber, to apply an electrical charge to the film and attract the metal atoms. In subsequent steps (not shown), the second adhesive layer is then applied to the metal layer, and the water-soluble polymer film is then applied to the second adhesive layer.

All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.

Claims

1. A laminated product comprising:

(b) one or more layers of water-soluble polymer film formed from a composition comprising poly(vinyl alcohol), wherein the composition does not contain amylose, wherein layer (b) is present on only one side of layer (a); and wherein layer (b) is adhered to layer (a) using an adhesive .

2. A laminated product according to claim 1, wherein the composition comprises 50 to 99% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition.

3. A laminated product according to claim 2, wherein the composition comprises 75 to 95% by weight poly(vinyl alcohol) as a proportion of the total weight of the composition.

4. A laminated product according to any one of claims 1 to 3, wherein the composition additionally comprises a plasticiser.

5. A laminated product according to claim 4, wherein the composition contains from 1 % to 30% by weight plasticiser as a proportion of the total weight of the composition.

6. A laminated product according to claim 4 or 5, wherein the plasticiser comprises a polyhydric alcohol selected from the group consisting of propylene glycol, ethylene glycol, glycerol, mannitol, erythritol, pentaerythritol, sorbitol, dipentaerythritol, and trimethylolpropane, or a mixture of any thereof.

7. A laminated product according to claim 6, wherein the plasticiser comprises glycerol.

8. A laminated product according to any one of claims 1 to 7, wherein layer (b) is a water-soluble polymer film obtained or obtainable by a method comprising:

(a) extruding the water-soluble polymer composition by passing the water-soluble polymer composition through an elongate chamber under the application of heat and one or more rotating screws, so as to partially or wholly melt the water- soluble polymer composition; and

(b) applying pressure to the melted water-soluble polymer composition to form the film.

9. A laminated product according to any one of claims 1 to 8, wherein the plant- based fibre sheet material is paper.

10. A laminated product according to any one of claims 1 to 8, wherein the plant- based fibre sheet material is cardboard.

11. A laminated product according to any one of claims 1 to 10, comprising: one or more layers of plant-based fibre sheet material, having one or more adhesive layer applied to only one side thereof; and one or more layers of water-soluble polymer film adhered to the one or more layers of the plant-based fibre sheet material by means of the one or more adhesive layers.

12. A laminated product according to any one of claims 1 to 10, comprising: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied thereto; one or more layers of a second adhesive applied to the one or more layers of the first adhesive; and one or more layers of water-soluble polymer film applied to one or more layers of the second adhesive.

13. A laminated product according to any one of claims 1 to 12, further including a metal layer.

14. A laminated product according to claim 13, wherein the metal layer comprises aluminium.

15. A laminated product according to claim 13 or claim 14, wherein the metal layer is passivated.

16. A laminated product according to claim 1, comprising: one or more layers of plant-based fibre sheet material, having one or more layers of a first adhesive applied thereto; one or more metal layers applied to the one or more first adhesive layers, the metal layers optionally being passivated; one or more layers of a second adhesive applied to the one or more metal layers; and one or more layers of water-soluble polymer film adhered to the one or more metal layers via the one or more layers of the second adhesive.

17. A laminated product according to any one of claims 1 to 16, wherein layer (a) includes an aperture which is fully or partially covered by layer (b).

18. A container having:

(b) a layer of water-soluble polymer in the form of a film; formed from a composition comprising poly(vinyl alcohol), wherein the composition does not contain amylose, wherein layer (b) is present on only one side of structure (a); and wherein layer (b) is adhered to layer (a) using an adhesive.

19. A container according to claim 18, wherein layer (b) is the water-soluble polymer film obtained or obtainable by a method comprising:

20. A container according to claim 18 or 19, the structure (a) having an aperture which is fully or partially covered by layer (b).

21. A method of producing the laminated product of any one of claims 1 to 17 or the container of any one of claims 18 to 20, comprising:

(i) providing layer or structure (a); (ii) applying an adhesive to layer or structure (a) and

22. A method according to claim 21 , wherein the adhesive is applied to only one side of layer or structure (a).

23. A method according to claim 21 , wherein step (iii) is carried out using the application of heat and/or pressure.

24. A method according to claim 21, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more adhesive layers to the plant-based fibre sheet material; and applying one or more layers of water-soluble polymer film to the adhesive layer such that it adheres thereto.

25. A method according to claim 21, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more adhesive layers to only one side of the plant-based fibre sheet material; and applying one or more layers of water-soluble polymer film to the adhesive layer such that it adheres thereto.

26. A method according to claim 21, wherein the adhesive layer is applied to the one or more layers of plant-based fibre sheet material by: coating one side of the plant-based fibre sheet layer using an adhesive layer in the form of a liquid; and allowing the liquid adhesive to dry.

27. A method according to claim 21, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more layers of a first adhesive to only one side of the plant-based fibre sheet material; applying one or more layers of a second adhesive to the one or more layers of the first adhesive; and applying one or more layers of water-soluble polymer film to the one or more layers of the second adhesive.

28. A method according to claim 27, wherein the one or more layers of the first adhesive are applied to the one or more layers of plant-based fibre sheet material by the application of heat and pressure.

29. A method according to claim 28, comprising: coating one side of the plant-based fibre sheet layer is with the first adhesive layer in the form of a liquid; and allowing the liquid adhesive to dry.

30. A method according to claim 26 or 29, wherein the adhesive is dried by curing.

31. A method according to claim 30, wherein the adhesive is cured by the application of ultraviolet radiation.

32. A method according to claim 27, wherein the one or more layers of the first adhesive are applied to the one or more layers of plant-based fibre sheet material at a temperature of 135 to 200°C.

33. A method according to claim 27 or 32, wherein the one or more layers of the first adhesive are applied to the one or more layers of plant-based fibre sheet material at a pressure of 1.5 to 4 bar.

34. A method according to claim 33, wherein the one or more layers of the first adhesive are applied to the one or more layers of plant-based fibre sheet material at a pressure of 2 to 3 bar.

35. A method according to any one of claims 27 to 34, wherein the one or more layers of the second adhesive are applied to the one or more layers of the first adhesive by the application of heat and pressure.

36. A method according to any one of claims 27 to 35, wherein the water-soluble polymer film is applied to the second adhesive layer by the application of pressure alone.

37. A method according to claim 36, wherein the water-soluble polymer film is applied to the second adhesive layer at a pressure of 5 to 50 bar.

38. A method according to claim 37, wherein the water-soluble polymer film is applied to the second adhesive layer at a pressure of 5 to 10 bar.

39. A method according to claim 21 or 24, comprising: providing one or more layers of plant-based fibre sheet material, applying one or more layers of a first adhesive to the plant-based fibre sheet material; applying one or more metal layers to the first adhesive layer; applying one or more layers of a second adhesive to the metal layer; and applying one or more layers of water-soluble polymer film to the second adhesive layer such that it adheres thereto.

40. A method according to claim 40, wherein the one or more layers of the first adhesive are applied to only one side of the plant-based fibre sheet material.

41. A method according to claim 39 or 40, wherein the metal layer is applied via a physical vapour deposition method.

42. A method according to claim 41 , wherein the physical vapour deposition method is a sputter deposition method.