WO2025202394A1

WO2025202394A1 - Bilayer film

Info

Publication number: WO2025202394A1
Application number: PCT/EP2025/058455
Authority: WO
Inventors: Hugo Thomas BARROUX; Marc RODRIGUEZ GARCIA; Ayaka Kamada
Original assignee: Xampla Ltd
Current assignee: Xampla Ltd
Priority date: 2024-03-29
Filing date: 2025-03-27
Publication date: 2025-10-02
Anticipated expiration: 2026-09-29

Abstract

The present invention relates to a film comprising: a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers; and a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers; to a process for the preparation of the film, to uses of the film and to methods of using the film.

Description

Bilayer Film

FIELD OF THE INVENTION

This invention relates to the field of heat-sealable, highly biodegradable films. The inventive films can be used for packing products, such as powder and liquid products, in sachets using current heat sealing equipment and at commercially viable production rates. In particular, the inventive films can be used in Vertical-Form-Fill-Seal (VFFS) or Horizontal-Form-Fill-Seal (HFFS) packaging equipment as well as in pod forming and filing equipment (such as the Hydroforma pod maker from Mespack) without requiring significant equipment modification. The inventive films use natural materials that are readily available, of low price and that have not required extensive or expensive chemical modifications. The films do not comprise synthetic polymers and are rapidly and completely biodegradable. The films can be soluble or dispersible in water.

BACKGROUND

Packaging materials made from renewable materials are of increasing interest and importance as environmental pressures dictate a move away from oil-based feedstock. Such packaging materials include films which are especially useful for wrapping and/or encapsulating products. Examples of products using films for packaging include sachets, capsules, pods, pouches, packets and bags. It is highly preferred if the packaging material, as well as being sourced from renewable materials, is highly biodegradable so as to minimise the problems of waste disposal. Typically, products made from renewable, natural feedstock, are highly biodegradable provided that they have not been chemically modified. Chemical modification can dramatically lower the biodegradability profile.

Some packaging films combine natural and synthetic materials. Such products typically have an improved environmental profile compared to equivalent products that use only synthetic materials. Plus, they can give an optimum balance of physical properties, such as strength and barrier resistance. However, the use of synthetic, typically non-biodegradable materials, inherently means that the biodegradability profile is not as good as materials that use natural raw materials.

Water-soluble films made from polyvinyl alcohol are widely available and widely used - for example in packaging of detergents. Often, they are marketed as being environmentally friendly. Examples include Monosol M-8630 from Monosol (now part of Kuraray). Typically, such films are soluble but actually have poor biodegradability in marine biodegradation tests and can accumulate in the environment. Some products and packaging applications require the packaging material itself to be edible. In this context, by “edible” it is meant that all of the materials are classified as being safe to eat whether or not they are digestible by humans or can provide human nutrition.

Many biopolymers, or materials of natural origin, can be used to make packaging films. Widely used examples of biopolymer films include starches and cellulose-based films. Starches are especially widely used due to their low cost and ready availability. Typically, the starches are chemically modified to improve their processability and functionality. One example of a modified starch is hydroxypropylated amylose starch. Other substituents may be hydroxyethyl or hydroxybutyl to form hydroxyether substitutions, or anhydrides such as maleic phthalic or octenyl succinic anhydride can be used to produce starch ester derivatives. Starch films typically have high tensile strengths at moderate humidity (such as between 30% and 50% relative humidity (RH) at 20 °C) but typically become much weaker at higher humidity unless they have been highly chemically modified. In particular, many starch films are very susceptible during storage at low temperatures, as starches are prone to retrogradation.

Many starch-based products, such as compostable bags, include significant levels of polybutene adipate terephthalate or PBAT to improve their processability and physical properties. PBAT is a biodegradable synthetic polymer. However, it is obviously obtained from non-renewable feedstock. Examples of starch-based films are those sold by Plantic Technologies Ltd (now part of Kuraray), which comprise modified starch and are available as both monolayer and multi-layer films.

Cellulose-based polymers and materials can also form films and are also widely used. Commonly, cellulose films are made from so-called “regenerated” cellulose wherein cellulose fibers are dissolved in carbon disulphide under alkaline conditions to form viscose. The viscose is then contacted with an acidic solution to “regenerate” the cellulose. Such processes are resource and energy intensive, and the resulting cellulose films are not water-soluble or water-dispersible at all, and they do not heat seal. Regenerated cellulose is used in NatureFlex films, which are cellulose-based compostable packaging films sold by Futamura. Other cellulose-materials include hyproxypropyl methyl cellulose (HPMC) and carboxymethyl cellulose (CMC). HPMC films have long been used in the medical field as a coating for tablets. However, HPMC itself requires significant effort to synthesise and thus is relatively expensive. It is not fully biodegradable due to the level of synthetic modification.

Other biopolymers that can be used to make films include proteins, both animal and plant sourced. Examples of animal proteins that can be used to form films include gelatine, collagen and casein. Gelatine is very widely used as a material for tablets and capsules. Casein (a milk protein collected from whey) has long been used to make plastic materials and can be formed into soluble and thermoformable pellets or sheets. Such materials do have very good biodegradability profiles but are animal sourced. As such, some people have moral and ethical issues with use of such products. In addition, in terms of efficient resource usage, it is typically environmentally better to be able to use a plant material directly rather than indirectly by feeding the plants to animals.

The use of biopolymers to make films and coatings is increasingly widespread and much effort continues to be put into using naturally sourced, renewable materials as replacements for non-renewable feedstock such as petroleum. The art is large and widespread and examples given below are for illustrative purposes only.

Many biopolymers are being used including plant-based, algae-based, fungi- based and animal-based materials. Examples of animal-based materials used to make films and coating include collagen, gelatine, chitosan, shellac and casein. Examples of plant-based materials used include starch, celluloses, proteins including pea, soy, corn and potato, pectin and so on. Examples of algae-based materials include alginates, carrageenan, furcellaran, and other gums. An example of a fungi-based material is pullulan. The reasons for using biopolymers in these applications range from wanting to use renewable feedstock to having more biodegradable materials to using more biocompatible materials for medical applications and even to provide edible packaging. Films and other packaging materials made from biopolymers can be soluble or insoluble. There is a need to use plant-derived, algae-derived or fungi-derived biopolymers rather than animal-derived biopolymers, both for ethical reasons and resource efficiency.

Biopolymers are complex materials and often harder to process and handle than synthetic polymers. Typically, they are susceptible to moisture and lose strength in high humidity environments. This susceptibility of biopolymers to moisture is typically an inherent feature due to their natural sources and is the major limitation to their more widespread use. Other issues include poorer thermoplastic properties including heat sealing of biopolymer films. Rapid and effective heat sealing without thermal damage is critical for industrial production of sachets and many package forms. The issues associated with many biopolymers, and especially their poor water resistance means that they are often either chemically modified to improve their properties, blended with synthetic polymers or laminated with other materials, including other biopolymers, so as to obtain a film having improved properties.

Polyhydroxyalkanoates (PHAs) are increasingly used due to their good thermoplastic properties. PHAs are natural biopolymers sourced from microbial fermentation but are slow to biodegrade and are insoluble. An example of an animal-based biopolymer is casein. EP3728477A1 describes a thermoplastic casein composition and packaging films made from thermoplastic casein. US9662400B2 describes chitosan films useful for medical applications. US6448378B2 describes soluble collagen films which are used to deliver drug treatments. A large-scale application for many edible films including collagen, alginate and protein-based films (amongst others) is for sausage casings. Sausage casings are monolayers and do not need to be heat sealed. US3408916 describes collagen films used for sausage casings. US6730340B1 describes a plant-based biopolymer blend for sausage casings based on mixtures of carrageenan and gellan gum.

Chemically modifying natural polymers or blending natural and synthetic polymers can improve the physical and processing properties of films made from these materials but will often reduce the overall biodegradability, is complex and does require the use of non-renewable materials.

Starch is cheap and can be chemically modified to improve its properties. US5498662 describes gas barrier films comprising a blend of poly(meth)acrylic acid and starch. Thermoplastic starches are available under the MATER-BI trade name supplied by Novamont. US20040242732A1 , EP2496644B1 and W02011080623A2 describe a biodegradable polymer composition based on chemically modified starch plus synthetic polymers. These materials can be used to form films.

Cellulose derivatives, and especially cellulose ethers such as hydroxypropyl methyl cellulose (HPMC), are used to make films, commonly for medical applications. EP1045000B1 describes an ingestible HPMC film. Such materials, whilst often safe to ingest, require high levels of synthetic modification. HPMC is often used fordrug coatings due to its selective pH solubility.

The use of laminated films to overcome some of the limitations of a single biopolymer is known. These laminates can comprise two or more layers. One of the layers can be a synthetic polymer. The synthetic polymer can be partially or fully biodegradable. The use of a synthetic polymer is not preferable compared to the use of biopolymers due to the use of non-renewable materials but the use of a combination of natural and synthetic materials can still be preferable compared to a fully synthetic material. The synthetic polymer layer, or highly modified biopolymer layer, typically provides enhanced barrier properties or enhanced heat sealing properties.

A common type of biopolymer-based laminate is a modified starch laminated with a synthetic polymer. An example of this is EP1581388B1 which describes a co-extrusion process to make a modified starch film laminated with a biodegradable polyester. US8715816 describes a multilayer film comprising a thermoplastic starch layer and a thermoplastic polyester layer. Other examples of composite laminated films are where the synthetic polymer is used to provide a heat-sealing layer.

EP2013290B1 describes a silk protein laminate film where the silk protein is laminated with another layer which could be either a different protein, such as collagen, or a synthetic polymer. There is no mention of heat sealing and the use of an animal product is non-preferred.

WO2023025769 discloses a monolayer carrageenan film used for preparing soluble laundry capsules. The capsules are formed by sealing the film using glues.

Marangoni Junior et al. in Carbohydrate Polymers, Vol 252, 117221 (2021) reviewed monolayer films of furcellaran or of blends of furcellaran with other biopolymers.

Accordingly, there exists a need to develop films with tuneable solubility and/or dispersibility that have sufficiently robust mechanical properties for them to be used as packaging films, including being handled in a manufacturing process and able to survive transportation and storage. A preferred feature is for foodstuff packaging to be edible, so as to further minimise waste and increase consumer convenience. A preferred feature is for non-foodstuff packaging to be biodegradable, so as to minimise environmental pollution.

SUMMARY OF THE INVENTION

Viewed from a first aspect, the present invention provides a film comprising: a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers; and a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers.

Viewed from a further aspect, the present invention provides a process for preparing a film as hereinbefore described, comprising the steps of:

(i) providing a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers;

(ii) providing a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers, and

(iii) forming said first layer and said second layer into said film.

Viewed from a further aspect, the present invention provides a film obtained by or obtainable by a process as hereinbefore described.

Viewed from a further aspect, the present invention provides a product enclosed by a film as hereinbefore described.

Viewed from a further aspect, the present invention provides a method of enclosing a product, comprising the steps of:

(i) wrapping the product in a film as hereinbefore described; and

(ii) heat sealing the film around the product to form a sachet.

Viewed from a further aspect, the present invention provides a sachet prepared by the method as hereinbefore described.

Viewed from a further aspect, the present invention provides the use of a film as hereinbefore described to enclose a product and/or to prepare a sachet.

Viewed from a further aspect, the present invention provides a method of releasing a product enclosed in a film as hereinbefore described, comprising the steps of:

(i) placing the enclosed product in water at a temperature of at least 40 °C; and

(ii) allowing the film to disperse, thereby releasing the product.

DETAILED DESCRIPTION OF THE INVENTION

It is preferable if non-traditional sources of biopolymers can be used whenever possible when sourcing feedstock for the inventive packaging films. Such non-traditional feedstock can be combined with traditional feedstock. “Traditional” relates to biopolymers typically used as human feedstuffs, for example starches. Particularly preferred biopolymers for the inventive films are red algae-derived polysaccharides which do not directly compete with food crops and do not require valuable farmland.

The suitability of the inventive films for commercial use does not just depend on their positive environmental profile. The films have to be processable in order to effectively enclose and protect a product. They have to be robust throughout the multiple environments experienced, including manufacture, storage and final use. They have to meet multiple different requirements, such as elongation and tensile strength. They must also be heat-sealable to form an enclosed and sealed packaging layer around a product. As used herein, such packaging is referred to as a “sachet” however this term includes items commonly described as pods, capsules, pouches, packets and bags etc.

In heat sealing, two films are pressed together and subjected to heat for a specified amount of time. The application of heat causes the diffusion and migration of polymer chains at the interface from film to film causing the formation of a bond as the seal is cooled. Not all polymer materials will heat seal as the mechanism depends on the behaviour of polymer chains at the interface. If these chains do not easily move or migrate, then the films will not seal. The ease of heat sealing is a complex interaction of polymer type, level of crystallinity, plasticisation, temperature and time.

Without wishing to be bound by theory, the poor heat-sealing behaviour of typical red algae-derived films is believed to result from the more compact structures that such materials seem to form when subjected to heat. This effect has been reported in the art and is used in some film making processes where heat treatments are used to make denser and less-permeable films. Production of red algae-derived films very often involves the application of heat to remove water. Heat sealing by definition requires heat to be applied. Thus, such materials would seem to be inherently poorly suited to heat sealing applications.

One established route for sealing biopolymer films is to use an adhesive to glue the films together. This can be combined with the application of heat and pressure to ensure good sealing. Such an approach is viable for certain types of equipment, such as the Hydroforma pod maker from Mespack, as the design of the drum allows the application of an adhesive layer on to one or both films. Nonetheless, adhesives come with their own draw backs such as the risk of contamination of the enclosed material or contamination of the adhesive by the enclosed product, particularly when a liquid or powder reduces seal robustness.

Many packing companies, however, use Vertical-Form-Fill Seal (VFFS) or Horizontal-Form-Fill Seal (HFFS) technology to make sachets. The films of the present invention are suitable for use in both.

In the VFFS process, film is drawn through the packing equipment vertically and folded together and sealed to form the sachet. Typically, a strip of film is folded around the filling head and sealed to form a cylinder or tube which is then sealed at the base, filled with the contents through the filling head and the top is then sealed. This approach can be used for both powders and liquids. The need to “pull” film through the equipment means that the film needs to have a minimum strength. The film cannot stretch too much otherwise it becomes very hard to control the correct positioning and alignment of the film. The film cannot be sticky to the touch as otherwise the friction on the film as the film is pulled through the equipment is too high. This means that spraying or applying a coating to one surface as the film strip is pulled through the packing line is just not practical.

HFFS equipment is very similar to VFFS equipment but the film travels in a horizontal direction. It is particularly useful to pack solid type commodities such as chocolate bars, etc.

The films of the present invention are also suitable for use in pod-making. In typical pod-making equipment, as in the Hydroforma pod maker by Mespack, a sheet of film is drawn down into a mold by the application of vacuum to form a cavity, material, such as a liquid detergent, is placed in the cavity and a second sheet of film is used to seal the cavity. The sealing can be by heat sealing or by solvent/adhesive sealing or combinations thereof.

The inventors have discovered that a bilayer film comprising a red algae-derived polysaccharide-rich layer and a layer comprising at least one material selected from plant-derived polysaccharides, fungi-derived polysaccharides and agar can overcome the various challenges highlighted above, based on selection of the materials and thicknesses of the layers. Such inventive films have good physical properties, such as tensile strength, over a wide range of conditions. They can be made from natural materials, do not require chemical modification and are of low cost and readily available. They can have a controlled solubility or dispersibility and have a very high biodegradability. As used herein, the term “water soluble film” or “water soluble sachet” refers to a film or sachet that dissolves in water at a temperature of 20 to 25 °C. As used herein, the term “water dispersible film” or “water dispersible sachet” refers to a film or sachet that disperses in water and achieves a result of “high”, “very high” or “maximum” when tested according to the method described in Example 8 at a temperature in the range 75°C to 90°C. Careful selection of material properties and the thicknesses of the layers means they can be heat sealed under industrially relevant conditions without damaging the sachets. The inventive films typically need to be sealed together by at least one surface of the second layer (i.e. at least one surface of the layer that comprises the at least one material selected from plant-derived polysaccharides, fungi-derived polysaccharides and agar), to get a good seal, whether a heat-seal or, when used in pod making equipment (such as the Hydroforma pod maker from Mespack), optionally including a solvent-seal. Trying to seal two first layers together (i.e. two layers comprising at least 20 wt% of at least one red algae-derived polysaccharide) will not provide a robust seal.

Any film needs to be heat-sealable within a short period of time for any production to be industrially viable. The design of a packing line mean means that the production rate is directly related to the time taken to perform the heat sealing. If it takes 5 seconds to perform the heat-sealing operation, then an individual line can at best only make 12 sachets a minute. This rate is far too low to be economically viable. Sealing times need to be 1 second or less, and preferably less than 0.5 seconds, for any production process to be economically viable for most products. Hence, the practical definition of heat sealability needs to include that, as well as being able to form robust seals, this needs to be achievable in 1 second or less and preferably in less than 0.5 seconds.

Heat sealing depends on the temperature at the interface of the two films being sealed to be high enough to start to melt the material at the interface so it starts to migrate and inter-penetrate. The temperature at the interface of the two films depends on the following variables.

(i) The temperature of the sealing plate(s) applying the heat. The higher the temperature, the quicker the interface will be heated.

(ii) The time that the heating plate is in contact with the film. Longer times allow more time for heat to be conducted through the film layers to the interface.

(iii) The pressure of the jaw. Higher pressure means faster heat transfer.

(iv) The thickness of the film that the heat is being conducted through. The thicker the film, the longer it will take for the interface at the middle to reach a sufficient temperature.

(v) The thermal conductivity of the layers forming the film. The rate at which heat is transferred across each layer in the film depends on the thermal conductivity of the film. The higher the thermal conductivity, the quicker heat is transferred to the interface.

As stated above, the time that the heating plate is in contact with the film for, needs to be as short as possible. One way to minimise the time required for the interface temperature to rise sufficiently to cause sealing is to use a high sealing temperature. This is effective but if the temperature is too high (such as > 160 °C), it will thermally damage the red algae-derived polysaccharide layer of the film that is in contact with the sealing plate, leading to visual and other defects around the seal.

Thus, the thermal stability of the red algae-derived polysaccharide-rich layer and the limited time available for heat sealing is crucial. According to the present invention, selection of the second layer composition that has an onset melting temperature of less than 100 °C, combined with a total thickness of between 20 pm and 120 pm of the two layers together forming the film, is preferred. The onset melting temperature is the temperature at which a composition begins to soften and partially melt. For heat sealing to occur, the materials at the interface must be at or above the onset melting temperature. Controlling the thicknesses of the films allows sufficient heat to be transferred to the interface in the time available whilst giving films of sufficient thickness and robustness to be practical.

Thus, a film comprising two layers - a first layer which is red algae-derived polysaccharide-rich and a second layer which is rich in at least one material selected from plant-derived polysaccharides, fungi-derived polysaccharides and agar - wherein the thicknesses of the two layers are controlled within specified limits and wherein the second layer has an onset melting temperature of less than 100 °C - gives a preferred biopolymer-based film that is robust and processable with current heat sealing equipment.

Accordingly, the present invention provides a film comprising: a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers; and a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers.

The films of the present invention comprise a first layer and a second layer. Preferred films of the present invention consist of two layers (i.e. the first layer and the second layer). However, the films of the present invention may comprise further layers. As would be understood by a skilled person, adjacent layers in the films of the present invention cannot be compositionally identical (i.e. adjacent layers much have compositions that are distinct enough to allow the two layers to be distinguished from each other by methods known in the art). In preferred films of the present invention, one surface of the second layer is sealed to one surface of the first layer.

The films of the present invention comprise a first layer comprising at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof. Algae are broadly classified into three categories depending on the pigments in their biomass: as Rhodophyta (red algae), Phaeophyta (brown algae), and Chlorophyta (green algae). The three categories of algae differ in their chemical content and types of carbohydrate, protein and lipids and this results in different biopolymers that can be extracted for industrial applications.

Macroalgae, otherwise known as seaweed, contain cellulose, as a structural support for cell walls, in different proportions and the voids within this structure are filled with varying levels of polysaccharides. Red seaweed contain significant amounts of agar, carrageenan and furcellaran.

In preferred films of the present invention, the red algae-derived polysaccharides are extracted from macroalgae.

Examples of red macroalgae (or red seaweed) include Eucheuma sp., Furcellaria sp., Gelidiella sp., Gracilaria sp., Gigartina sp., Gelidium sp., Gymnogongrus sp., Hypnea sp., Kappaphycus sp., Lemanea sp., Mastocarpus sp., Palmaria sp., Porphyra sp., Schmitzia sp., Chondrus sp., Mastocarpus sp., Acrochaetium sp., Audouinella sp., Polysiphonia sp., Solieria sp., Vertebrata sp., Pterocladia sp., Acanthopeltis sp., Asparagopsis sp., preferably, Euchema sp., Furcellaria sp., Gelidium sp. or Gracilaria sp., more preferably Euchema cottonii.

In alternative preferred films of the present invention, the red algae-derived polysaccharides are extracted from microalgae. Microalgae are microscopic algae not visible to the naked eye. They are unicellular organisms but can be found in aggregates.

The microalgae and macroalgae used to obtain the red algae-derived polysaccharides for the films of the present invention may be obtained from the natural environment (e.g. retrieval when washed up to land by coastal waters), produced through aquaculture in ponds, tanks or tubes or be engineered to produce algae-derived polysaccharides in controlled conditions or industrial-like settings.

Microalgae and macroalgae are sometimes grown to capture carbon from carbon dioxide or methane for the purpose of reducing greenhouse gases in the atmosphere. The algae is then the source for extraction of algae-derived polysaccharides.

Alternatively, nature identical polymers can be synthesised chemically outside the algae cells yielding the same materials as would be extracted from naturally grown or cultivated algae.

Accordingly, as used herein the phrase “red algae-derived polysaccharides” refers to polysaccharides obtained from red macroalgae or red microalgae, be that via an extraction process performed on naturally grown or cultivated red macroalgae or red microalgae, or via synthetic processes to yield the same materials that would be present in naturally grown or cultivated red macroalgae or red microalgae.

As used herein the phrase “red seaweed-derived polysaccharides” (or “red macroalgae-derived polysaccharides”) refers to polysaccharides obtained from red macroalgae, be that via an extraction process performed on naturally grown or cultivated red macroalgae, or via synthetic processes to yield the same materials that would be present in naturally grown or cultivated red macroalgae. Carrageenans, agar and furcellaran are part of a family of polysaccharides typically obtained from the cell walls of red algae. This is in contrast to polysaccharides derived from brown algae, such as alginates, or green algae, such as ulvans.

Carrageenans, agar and furcellaran are all polysaccharides with a galactose backbone, but differ in the proportion and location of the sulphate ester groups and in the proportion of 3,6-anhydrogalactose.

Carrageenans are linear anionic sulphated polygalactans formed by disaccharide repeating units and which consists of alternating 3-linked p-d- galactopyranose or 4-linked a-d-galactopyranose or 4-linked 3,6-anhydro-a-d- galactopyranose. There are six different categories based on the degree of free sulphation, but only three are available commercially: iota, kappa and lambda. Carrageenans are used as an additive in the cosmetics, pharmaceutical and food industry mainly for controlling product viscosity and as an emulsifier. Kappa-carrageenan in particular is classified as a food additive as E407. Processed Euchema algae is classified as a food additive number E407a.

Agar is a linear sulphated polygalactan. It is a heterogeneous polysaccharide comprising agarose (typically 70%) and agaropectin (typically 30%) polymers. It is well known for its gelation properties with most production used in food applications (e.g. it is classified as a food additive as E406) where it can substitute for animal-derived gelatine, as well as in microbiology assays and techniques. Agarose is a linear polysaccharide of repeating units of p-1 ,3-linked-d-galactose and a-1 , 4-linked 3,6-anhydrous-L galactose. Agaropectin has the same backbone as agarose but is slightly branched and contains many anioinic groups such as pyruvate, sulphate, and glycuronate.

Furcellaran is an anionic sulfated polysaccharide. It is classified in conjunction with kappa-carrageenan (E407) for use as food additives under European Union legislation. Furcellarans are salts of a linear polymer, composed of [^4)-3,6-anhydro-d- galactopyranose-(1^3)-galactopyranose-4'-sulphate -(1— >] structural units). The weightaverage molar mass values reported in the literature vary between values from around 290-500 kDa.

Thus, in films of the present invention, the at least one red algae-derived polysaccharide in the first layer is selected from carrageenan and furcellaran or mixtures thereof. Preferably, the at least one red algae-derived polysaccharide in the first layer is carrageenan, more preferably iota-carrageenan, kappa-carrageenan or lambda- carrageenan or mixtures thereof, most preferably kappa-carrageenan.

In preferred films of the present invention, the at least one red algae-derived polysaccharide in the first layer is a red seaweed-derived polysaccharide. Thus, in films of the present invention, the at least one red seaweed-derived polysaccharide in the first layer is selected from carrageenan and furcellaran or mixtures thereof. Preferably, the at least one red seaweed-derived polysaccharide in the first layer is carrageenan, more preferably iota-carrageenan, kappa-carrageenan or lambda-carrageenan or mixtures thereof, most preferably kappa-carrageenan.

In preferred films of the present invention, the first layer has a thickness between 15 pm and 115 pm.

In preferred films of the present invention, the second layer has a thickness between 5 pm and 80 pm.

Preferred films of the present invention have a thickness between 20 pm and 120 pm, preferably 30 pm to 100 pm.

In preferred films of the present invention, the second layer has an onset melting temperature of less than 100 °C, preferably less than 85 °C, preferably less than 80 °C, determined as described in Example 3 of the specification.

In alternative preferred films of the present invention, the second layer has an onset melting temperature of at least 55 °C, determined as described in Example 3 of the specification.

In particularly preferred films of the present invention, the second layer has an onset melting temperature in the range of 55 to 100 °C, preferably from 55 to 85 °C, determined in Example 3 of the specification.

In preferred films of the present invention, the second layer comprises at least one plant-derived polysaccharide, wherein said plant-derived polysaccharide is a starch.

A starch is a carbohydrate polymer that is the main energy store in plants. Starches consist of amylose and/or amylopectin. Amylose is a linear polysaccharide chain that is made up of glucose monomers joined by a o(1 ,4) glycosidic linkage and it constitutes around 20-30% of starch. Amylopectin is a highly branched polymer made up of glucose subunits. It is made up of linear chains of glucose units that are linked by o(1 ,4) glycosidic linkages along with a number of side chains that branch the structure by o(1 ,6) glycosidic linkages and constitutes 70-80% of starch. In the native form, starches are typically in the form of semi-crystalline granules. Sources of starch include but are not limited to fruits, seeds, and rhizomes or tubers of plants.

Some starches are classified as waxy starches. A waxy starch consists essentially of amylopectin and lacks an appreciable amount of amylose. Typical waxy starches include waxy maize starch, waxy rice starch, waxy potato starch, and waxy wheat starch.

Alternatively, some starches are classified as high amylose starches. Modified starches are prepared by physically, enzymatically, or chemically treating native starch to change its properties. Starches may be modified, for example, by enzymes, by heat treatment, oxidation, or reaction with various chemicals.

In the films of the present invention, the starch may be a native starch or a modified starch, or a mixture thereof.

In preferred films of the present invention, the starch is selected from wheat starch, potato starch, pea starch, waxy potato starch, maize starch, waxy maize starch, high amylose maize starch, tapioca starch, cassava starch, rye starch, sorghum starch, chickpea starch, soy starch, or a mixture thereof, preferably potato starch.

In preferred films of the present invention, the starch is selected from wheat starch, potato starch, pea starch, maize starch, high amylose maize starch, tapioca starch, cassava starch, rye starch, sorghum starch, chickpea starch, soy starch, or a mixture thereof, preferably potato starch.

In alternative preferred films of the present invention, the starch is a modified starch selected from acid-treated starch, dextrin, alkaline-modified starch, bleached starch, oxidized starch, enzyme-treated starch, maltodextrin, cyclodextrin monostarch phosphate, distarch phosphate, acetylated starch, hydroxypropylated starch, hydroxyethyl starch, starch sodium octenyl succinate, starch aluminium octenyl succinate or cationic starch, or a mixture thereof, preferably acid-treated starch.

In preferred films of the present invention, the second layer comprises at least one fungi-derived polysaccharide, wherein said fungi-derived polysaccharide is pullulan. Pullulan is a linear polysaccharide composed of 3 maltotriose units linked by an a(1- 4) glycosidic bond, where successive maltotriose units are linked to each other by a(1- 6) glycosidic linkages. It is produced by the fungus Aureobasidium pullulans by starch fermentation. Pullulan is mainly used by cells to resist desiccation and predation. The presence of this polysaccharide also facilitates diffusion of molecules both into and out of the cell. It is used as a vegetarian substitute for gelatine in pharmaceutical capsules and in other medical applications such as tissue engineering. It is also used as a food additive under E number E1204.

In preferred films of the present invention, the second layer comprises agar. As described above, agar is a red algae-derived polysaccharaide and is a mixture of two components, mainly agarose and agaropectin.

In preferred films of the present invention, the second layer comprises 40-95 wt% of at least one material selected from plant-derived polysaccharides, wherein said plant- derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi- derived polysaccharide is pullulan, and agar based upon the total weight of the second layer, preferably 50-80 wt%, more preferably 55-75 wt%. Alternative preferred films of the present invention comprise 1-80 wt% of one or more of at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar based upon the total weight of the film, preferably 7-70 wt%, more preferably 15-50 wt%.

Preferred films of the present invention comprise based upon the total weight of the film 3-90 wt.-%, preferably 15-85 wt.-%, more preferably 25-80 wt.-%, most preferably 35-70 wt.-%, of red algae-derived polysaccharides selected from carrageenan, furcellaran, and mixtures thereof determined according to the method described in Glueck et al., 1980, Zeitschrift fur Lebensmittel-Untersuchung und - Forschung, 170, 272-279.

An analytical method for identification and quantification of carrageenan, furcellaran, agar and further non-red algae derived polysaccharides in dairy products was described by Glueck U and Their HP, 1980. Quantitative determination of some thickeners in dairy products. Zeitschrift fur Lebensmittel-Untersuchung und - Forschung, 170, 272-279. The polysaccharides are extracted from foodstuff and then fat, starch, proteins and carbohydrates are removed by extraction or degradation. This method is equally applicable for determining the red algae-derived polysaccharide content of the inventive films. The resulting polysaccharide fraction is analysed by gas chromatography after hydrolysis with trifluoroacetic acid, and derivatisation of the resulting monosaccharides with hydroxylamine hydrochloride and acetic acid anhydride to form the aldonitrilacetate derivatives. The polysaccharides can be qualitatively identified by their characteristic monosaccharide pattern, and quantified via the single monosaccharide peaks. In the case of carrageenan, the only hydrolysis product is galactose.

A number of other analytical methods were developed for the determination of carrageenan. These methods include GC, HPLC, colorimetry, electrophoresis, immunoassays and potentiometry. An overview is presented in the review of Roberts MA and Quemener B, 1999. Measurement of carrageenans in food: challenges, progress, and trends in analysis. Trends in Food Science and Technology, 10, 169-181.

Preferred films of the present invention comprise 10-50 wt% of one or more organic plasticisers based upon the total weight of the film, preferably 15-45 wt%, more preferably 20-40 wt%.

Preferably, the one or more organic plasticisers in the first layer are independently selected from the group consisting of: a) polyols formed by from 1 to 20 repeating hydroxylated units each unit including from 2 to 6 carbon atoms, provided that when the polyol is formed by only one repeating unit it has at least 4 carbon atoms, with the exclusion of sorbitol, b) ethers, thioethers, organic esters, acetals and amino-derivatives of polyols formed by from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms with the exclusion of acetic esters of glycerine, triethyl citrate and tributyl citrate, c) polyol reaction products having from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms with chain extenders, d) polyol oxidation products having from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms including at least one aldehydic or carboxylic functional group or mixtures thereof.

More preferably, the one or more organic plasticisers in the first layer are independently selected from glycerol, diglycerin, dipropylene glycol, tetraethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, trimethyl propane, poly ether polyols, 2-methyl-1 ,3-propanediol, ethanolamines, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, fatty acids (e.g. oleic acid), monoglycerides, diglycerides, triglycerides, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids and organic acids (e.g. lactic acid, citric acid, glycolic acid, malic acid, tartaric acid, or gluconic acid), or a mixture thereof, with a mixture of glycerol, sorbitol and oleic acid being most preferred. Preferably, the plasticiser is plant-derived.

In preferred films of the present invention, the one or more organic plasticisers are present in the first layer in an amount of 10-50 wt%, more preferably 20-40 wt% on a dry solids basis.

In alternative preferred films of the present invention, the weight ratio of the at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof to organic plasticiser in the first layer is in the range 4:1 to 1 :1.

Preferably, the one or more organic plasticisers in the second layer are independently selected from the group consisting of: a) polyols formed by from 1 to 20 repeating hydroxylated units each unit including from 2 to 6 carbon atoms, provided that when the polyol is formed by only one repeating unit it has at least 4 carbon atoms, with the exclusion of sorbitol, b) ethers, thioethers, organic esters, acetals and amino-derivatives of polyols formed by from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms with the exclusion of acetic esters of glycerine, triethyl citrate and tributyl citrate, c) polyol reaction products having from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms with chain extenders, d) polyol oxidation products having from 1 to 20 repeating hydroxylated units each including from 2 to 6 carbon atoms including at least one aldehydic or carboxylic functional group or mixtures thereof.

More preferably, the one or more organic plasticisers in the second layer are independently selected from glycerol, diglycerin, polyethylene glycol, propylene glycol, dipropylene glycol, tetraethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, trimethyl propane, poly ether polyols, 2-methyl-1 ,3-propanediol, ethanolamines sorbitol, mannitol, xylitol, triethyl citrate, fatty acids (e.g. oleic acid), monoglycerides, diglycerides, triglycerides, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids and organic acids (e.g. lactic acid, citric acid, glycolic acid, malic acid, tartaric acid or gluconic acid), or a mixture thereof, with a mixture of glycerol and, sorbitol being most preferred. Preferably, the plasticiser is plant-derived.

Alternatively, the one or more organic plasticisers in the second layer is preferably a sugar surfactant including at least one sugar moiety. Sugar surfactants are preferably composed of at least one, preferably more than two, monosaccharide units linked glycosidically and may include what are termed ‘sugar’ moieties (two monosaccharide units) or from three monosaccharides. The monosaccharides of the sugar moiety may be of the same type (homopolysaccharide) or different (heterosaccharide). Preferably, the sugar surfactant is ionic, more preferably it is anionic, cationic, or amphoteric. More preferably, the sugar surfactant is anionic. The sugar surfactant is preferably selected from functionalised alkyl polyglycosides, fatty acid glucamides, glycinates, glycolipid biosurfactants, such as rhamno-based surfactants (e.g. rhamnolipids) or sophorolipids, or mixtures thereof.

In preferred films of the present invention, the one or more organic plasticisers are present in the second layer in an amount of 10-50 wt%, more preferably 20-40 wt% on a dry solids basis.

In preferred films of the present invention, the weight ratio of the at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar to the one or more organic plasticisers in the second layer is in the range 4: 1 to 1 : 1.

As would be understood by a skilled person, the one or more organic plasticisers can either be the same in the first and second layer, or the one or more organic plasticisers in the first and second layer can be different. The plasticiser may be emulsified before incorporation to the mixture with the remaining film materials by use of an emulsifier, preferably a non-ionic emulsifier, such as a polysorbate. When the film is intended to package a foodstuff, the plasticiser must be suitable for human consumption.

Preferred films of the present invention comprise 5-35 wt.-%, more preferably 7.5- 25 wt.-%, most preferably 10-20 wt.-% water based upon the total weight of the film at 55% relative humidity and 20 °C.

In preferred films of the present invention, the first layer further comprises at least one plant-derived or fungi-derived polysaccharide, more preferably a plant-derived polysaccharide, most preferably a starch.

Preferred films of the present invention further comprise one or more additives, such as gums, oils, fragrances, dyes, pigments, bittering agents, opacifiers, antimicrobial agents such as thymol, anti-blocking agents, lubricating agents or structural enhancers such as cellulose nanofibers, cellulose nanocrystals and cellulose fibres.

Particularly preferred films of the present invention further comprise a bittering agent. Bittering agents can impart a safety feature to films of the present invention that are not intended to be edible, i.e. to make them unpalatable in the instance that a child or animal were to try and eat them. Preferably, the bittering agent is selected from: capsicinoids, vanillyl ethyl ether, vanillyl propyl ether, vanillyl butyl ether, vanillin propylene, glycol acetal, ethylvanillin propylene glycol acetal, gingerol, 4-(1- menthoxymethyl)-2-(3'-methoxy-4'-hydroxy-phenyl)-1 ,3-dioxolane, pepper oil, pepperoleoresin, gingeroleoresin, nonylic acid vanillylamide, jamboo oleoresin, Zanthoxylum piperitum peel extract, sanshool, sanshoamide, black pepper extract, chavicine, piperine, spilanthol, allyl isothiocyanate, resinferatoxin and mixtures thereof. Particularly preferred bittering agents include capsaicinoids, which includes capsaicin, dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin, homocapsaicin, and nonivamide. A particularly preferred bittering agent is capsaicin.

Bittering agents may also be selected from denatonium salts such as denatonium benzoate, denatonium saccharide, denatonium chloride benzoic benzylamine amide, trichloroanisole, methyl anthranilate and quinine (and salts of quinine). Further examples of bittering agents include flavonoids such as quercefin and naringin, naringin, sucrose octaacetate, quassinoids such as quassin and brucine, and agents derived from plant or vegetable matter, such as chemical compounds derived from chilli pepper plants, those derived from a plant species of the genus cynaro, alkaloids and amino acids. Preferably, the bittering agent is selected from the group consisting of denatonium benzoate (e.g. Bitrex®), denatonium saccharide, quinine or a salt of quinine. The chemical name of denatonium is phenylmethyl-[2-[(2,6-dimethylphenyl)amino]-2-oxoethyl]- diethylammonium. The bittering agent may have a bitter value of between 1000 and 10,000,000 as measured using the standardized process that is set forth in the European Pharmacopoeia (5th Edition, Stuttgart 2005, Volume 1 , General Monograph 15 Groups, 2.8.15 Bitterness Value, p. 278).

In preferred films of the present invention, the bittering agent is present in the film in a range of 100 to 5000 ppm, preferably 200 to 3000 ppm, more preferably 500 to 2000 ppm, based on the total weight of the bittering agent and film.

As would be understood by a skilled person, said bittering agent can be present in the first and/or second layer.

Additionally or alternatively, the bittering agent may be provided as a powdered bittering agent in a powder coating applied to the outer surface of the film. As used herein, the term "outer surface” refers to the surface of the film that, in use, will primarily be in contact with the external environment and not the product being enclosed. As used herein, the term “inner surface” refers to the surface of the film that, in use, will primarily be in contact with the product to be enclosed and not the external environment. As would be understood by a skilled person, the films of the present invention can be sealed around a product using either a fin seal or a lap seal. A fin seal is preferred. As used herein, the term “fin seal” or “fold-over seam” refers to the sealing arrangement where at least a portion of two inner surfaces of film are sealed together. As would be understood by a skilled person, a fin seal can be prepared by folding over a single piece of film, or sealing together two separate films. As used herein, the term “lap seal” or “overlap seam” refers to the sealing arrangement where at least a portion of the outer surface of film is sealed together with at least a portion of the inner surface of film. As would be understood by a skilled person, a lap seal can be prepared by folding over a single piece of film, or sealing together two separate films.

Preferred films of the present invention further comprise a phyllosilicate. Preferably, said phyllosilicate is a serpentine mineral, a clay mineral, a chlorite mineral or a mica mineral, or mixtures thereof. Preferably, said clay mineral is selected from bentonite, kaolinite, pyrophyllite, vermiculite and a smectite (e.g. montmorillonite, cloisite, laponite, hectorite etc.), or mixtures thereof.

As would be understood by a skilled person, said phyllosilicate can be present in the first and/or second layer.

In preferred films of the present invention, the film includes a powder coating on an outer surface, and the powder coating includes a powdered lubricating agent. As would be understood by a skilled person, a powder coating does not equate to the first layer or second layer of the films of the present invention. Rather, a powder coating is applied to the final film and is typically a discontinuous covering of discreet individual particles over the surface of the film. The powder coating may be applied to least 50%, preferably at least 60%, at least 70%, even more preferably at least 80%, most preferably at least 90% percent by area of the outer surface of the film. The powder coating can be applied by any known technique such as spray-coating or passing the film through a falling curtain of powder coating composition. The powder coating may be applied to the outer surface of the film at a rate of 0.5 to 10mg per 100cm², preferably not more than 5mg per 100cm², and further preferably in the range of 1.25 to 2.5mg per 100cm². The powder coating may be applied to or is present on the outer surface of the film in an amount of 100 ppm or more, preferably 200 ppm or more, more preferably 300 ppm or more, based on the total weight of the powder coating and the film. Particularly preferably, the powder coating is applied to or is present on the outer surface of the film in a range of 100 to 5000 ppm, preferably 200 to 3000 ppm, more preferably 300 to 2000 ppm.

Preferred films of the present invention have a heat sealing strength of at least 40 N/m as measured by ASTM F88/F88M-15 at 55% relative humidity and 20 °C, more preferably at least 60 N/m, even more preferably at least 80 N/m, even more preferably at least 100 N/m, most preferably at least 120 N/m after the film has been conditioned at 55 % relative humidity at 20 °C for at least one hour and then sealed as either a fin seal or a lap seal at a temperature of 140 °C and a pressure of between 1 and 3 bar applied for a time of 1 second.

Preferred films of the present invention are substantially free of cations of divalent metals selected from calcium, magnesium, strontium, and zinc. As used herein, the phrase “substantially free of cations of divalent metals selected from calcium, magnesium, strontium, and zinc” means that the film contains less than 1 wt% of cations of divalent metals selected from calcium, magnesium, strontium, and zinc (i.e. Ca²⁺, Mg²⁺, Sr²⁺, and Zn²⁺), preferably less than 0.5 wt%, more preferably less than 0.1 wt%, more preferably less than 0.05 wt%, more preferably less than 0.01 wt%, more preferably less than 0.005 wt%, more preferably less than 0.001 wt%, more preferably less than 0.0005 wt%, most preferably 0 wt% based upon the total weight of the film, as measured by atomic absorption spectrophotometry (AAS). AAS detects elements in samples through the application of characteristic wavelengths of electromagnetic radiation from a light source. Individual elements will absorb wavelengths differently, and these absorbances are measured against standards. Preferably, flame atomic absorption spectrophotometry (FASS) is used to analyse the elements calcium, magnesium, strontium and zinc. A typical sample preparation procedure for solid samples involves digestion with a concentrated acid; for example, HNO3, HCI, or H2SO4. Other sample preparation methods, including microwave and high-pressure digestion, are also used to break up samples. After dilution of the digested solutions, samples can be directly injected into the spectrophotometer.

Preferably, the films of the present invention do not contain any cations of divalent metals selected from calcium, magnesium, strontium, and zinc (i.e. they contain 0 wt% cations of divalent metals selected from calcium, magnesium, strontium, and zinc based upon the total weight of the film). As would be understood by a skilled person, the films of the present invention may, however, contain contaminant levels of cations of divalent metals selected from calcium, magnesium, strontium, and zinc. This may occur, for example, if the process used to prepare the films involves the use of hard water, which contains around 200 mg/l calcium carbonate and around 200 mg/l magnesium carbonate. Preferred films of the present invention are made exclusively from food-grade materials.

Preferred films of the present invention are more than 75 %, more preferably more than 80 %, even more preferably more than 85 %, even more preferably more than 90 %, most preferably more than 95 % biodegradable in fresh water, according to ISO 14851 (2019) after 28 days testing.

Preferred films of the present invention are more than 75 %, more preferably more than 80 %, even more preferably more than 85 %, even more preferably more than 90 %, most preferably more than 95 % biodegradable in marine water, according to ASTM D6691 after 28 days testing.

The present invention also provides a process for preparing a film as hereinbefore described, comprising the steps of:

(ii) providing a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers; and

(iii) forming said first layer and said second layer into said film. In preferred processes of the present invention, step (iii) involves depositing onto and adhering one surface of the second layer to one surface of the first layer. As would be understood by a skilled person, depositing onto and adhering one surface of the second layer to one surface of the first layer does not require there to be a full contact at all points along the interface. Rather, discontinuous contact is envisaged whereby voids, pockets or compartments can be created. Alternatively, continuous contact is also envisaged such that depositing onto and adhering one surface of the second layer to one surface of the first layer does require there to be a full contact at all points along the interface. As would be understood by a skilled person, continuous contact or discontinuous contact can also be achieved when sealing films of the present invention together.

In preferred processes of the present invention, step (i) involves use of a preformed first layer.

In alternative preferred processes of the present invention, step (ii) involves use of a pre-formed second layer.

In preferred processes of the present invention, step (i) involves forming said first layer. Preferably, said first layer is formed by a casting method, a lamination method or an extrusion method.

In preferred processes of the present invention, step (ii) involves forming said second layer. Preferably, said second layer is formed by a casting method, a lamination method or an extrusion method.

A preferred process of the present invention comprises the steps of:

(a) mixing the at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof and the at least one organic plasticiser in water to form a mixture (a);

(b) forming the mixture (a) into said first layer on a surface;

(c) mixing the at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and the at least one organic plasticiser in water to form a mixture (b); and

(d) forming the mixture (b) into said second layer on said first layer.

Preferably, step (a) involves additionally mixing at least one plant-derived or fungi-derived polysaccharide to form said mixture (a).

Preferably, step (a) is conducted at a temperature in the range 15 to 100 °C, preferably 20 to 80 °C, more preferably 25 to 60 °C.

Preferably, in step (b) mixture (a) is at a temperature in the range 15 to 100 ° C, preferably 15 to 80°C and more preferably 15 to 50°C. Preferably, step (c) is conducted at a temperature in the range 20 to 100 °C, more preferably 50 to 90°C.

Preferably, in step (d) mixture (b) is at a temperature in the range 30 to 70°C, more preferably 30 to 50 °C (e.g. 40 °C).

Preferably, prior to step (d) mixture (b) is degassed.

A preferred process of the present invention comprises the steps of:

(a) mixing the at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and the at least one organic plasticiser in water to form a mixture (c);

(b) forming the mixture (c) into said second layer on a surface;

(c) mixing the at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof and the at least one organic plasticiser in water to form a mixture (d);

(d) forming the mixture (d) into said first layer on said second layer.

Preferably, step (a) is conducted at a temperature in the range 20 to 100 °C, more preferably 50 to 90°C.

Preferably, in step (b) mixture (c) is at a temperature in the range 30 to 70 °C, more preferably 30 to 50 °C (e.g. 40 °C).

Preferably, prior to step (b) mixture (c) is degassed.

Preferably, step (c) involves additionally mixing at least one plant-derived or fungi-derived polysaccharide to form said mixture (d).

Preferably, step (c) is conducted at a temperature in the range 15 to 100 °C, preferably 20 to 80°C, more preferably 25 to 60 °C.

Preferably, in step (d) mixture (d) is at a temperature in the range 15 to 100 ° C, preferably 15 to 80°C and more preferably 15 to 50°C.

In a preferred process of the present invention the one or more layers are independently made by casting or blown film extrusion, preferably by casting, more preferably solvent casting.

Solvent casting can be a two-step process where a first layer of material is cast onto a substrate such as Mylar®, or corona treated Mylar® or a metal belt. The mixture cast can be at room temperature or heated. Immediately after coating the material is dried in an oven and the film is reeled onto a core. The roll of first layer (which may still be on the Mylar®) is unpeeled from the roll and reeled through the line again so a second layer can be cast on top of the first layer and again dried in the oven. Again the mixture cast can be at room temperature or heated. This process can be described as a “wet- on-dry process”. To control the casting thickness, the casting line is equipped with a system of metallic rollers where the gap between rollers controls the wet thickness of the coating. The line speed and oven temperature are adjusted to obtain the desired dry film thickness and final moisture content. The final dry film is peeled from the backing substrate and is then rolled onto a core and stored until required for wrapping or enclosing a product and optionally sealing the film to form a sachet.

Solvent casting can also be a one-step continuous process where a first layer of material is cast onto a substrate such as Mylar®, corona treated Mylar® or a metal belt. The mixture cast can be at room temperature or heated. After coating and drying, or partially drying, in an oven, the second layer can be cast on top of the first layer and finally dried in a second oven. Again the mixture cast can be at room temperature or heated. This process can be described as a “wet-on-wet process” or “wet-on-semi-dry process”. To control the casting thickness, the line is equipped with a system of metallic rollers where the gap between rollers controls the wet thickness of the coatings. The line speed and oven temperatures are adjusted to obtain the desired final dry film thickness and final moisture content. The final dry film is peeled from the backing substrate and is then rolled onto a core and stored until required for wrapping or enclosing a product and optionally sealing the film to form a sachet.

In both solvent casting processes, it is important to that the final roll of film can be unwound easily and without damaging the film. This is necessary either in the intermediate part of the wet-on-dry process or when using the final film in a product packing line.

Preferred processes of the present invention further comprise a step of microperforating the film. Such as step can be advantageous when the product to be enclosed by the film is, for example, a powdered product as the microperforation can help with release of the powder during use.

The present invention also provides a film obtained by or obtainable by a process as hereinbefore described.

The present invention also provides a product enclosed by a film as hereinbefore described.

In a preferred product of the present invention, the film is substantially free of cations of divalent metals selected from calcium, magnesium, strontium, and zinc. Preferably, the film does not contain any cations of divalent metals selected from calcium, magnesium, strontium, and zinc.

In a preferred product of the present invention, the film is made exclusively from food-grade materials.

In an alternative preferred product of the present invention, the film is more than 75 %, more preferably more than 80 %, even more preferably more than 85 %, even more preferably more than 90 %, most preferred more than 95 % biodegradable, in fresh water according to ISO 14851 (2019) after 28 days testing.

In an alternative preferred product of the present invention, the film is more than 75 %, more preferably more than 80 %, even more preferably more than 85 %, even more preferably more than 90 %, most preferably more than 95 % biodegradable in marine water, according to ASTM D6691 after 28 days testing.

A preferred product of the present invention is a foodstuff, a pharmaceutical product, a cleaning product, an agricultural product (e.g. an animal feed or medication), a chemical product or a cosmetic product.

Water activity is the ratio at equilibrium between the vapour pressure of water over a sample and the vapour pressure of pure water under the same conditions (e.g. temperature). It can be referred to as “free water” indicating that it is unbound and available. Water activity can be measured easily in commercially available devices, for example the HygroPalm23-AW from Rotronic.

Preferably, the product of the present invention is a solid or powdered product having a water activity of less than 0.65.

Also preferably, the product of the present invention is a solid or powdered product having a water activity in the range 0.25 to 0.65, more preferably in the range 0.35 to 0.55 (e.g. 0.45).

An alternative preferred product of the present invention is a solid product selected from a soup or flavouring preparation (e.g. a stock cube), a personal cleanser (e.g. a soap bar, body scrub or solid shampoo), a laundry detergent tablet or bar or a dishwasher detergent tablet.

Preferably, the product of the present invention is a stock cube or a laundry detergent tablet or a dishwasher detergent tablet.

An alternative preferred product of the present invention is a powdered product selected from a powdered food, a powdered drink, powdered milk, powdered soup, powdered hot chocolate, powdered coffee, powdered tea, tea leaves, soap flakes, powdered laundry detergent, and powdered shampoo.

Preferably, the product of the present invention is a powdered drink.

Also preferably, the product of the present invention is an aqueous liquid product selected from a homecare or cleaning product or a hair care or body care product having a water activity of less than 0.65.

Also preferably, the product of the present invention is an aqueous liquid product having a water activity in the range 0.25 to 0.65, more preferably in the range 0.35 to 0.55 (e.g. 0.45). An alternative preferred product of the present invention is an oil or water-less liquid, such as a body care oil or an anhydrous liquid detergent.

The present invention also provides a method of enclosing a product, comprising the steps of:

(i) wrapping the product in a film as hereinbefore described; and

(ii) heat sealing the film around the product to form a sachet.

As would be understood by a skilled person, the heat sealing step requires contact between sections of film comprising the at least one material selected from plant- derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi- derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar. For example, a composite film comprising starch and carrageenan can be sealed against another composite film comprising starch and carrageenan, or to itself. However, if the film is a multilayer film comprising, for example, a starch layer and a carrageenan layer, the films typically need to be sealed together by at least one starch-rich surface to get a good seal. Trying to seal carrageenan layers together will not provide a robust seal. Also as would be understood by a skilled person, a starch-starch seal will generally be stronger than a starch-carrageenan seal, thereby allowing the seal strength to be tuneable.

In a preferred method of the present invention, the duration of step (ii) is less than 2 seconds, more preferably less than 1 second, most preferably less than 0.5 seconds.

In preferred methods of the present invention, step (ii) is conducted at a temperature of less than 160 °C, more preferably less than 140 °C, most preferably less than 120 °C.

The present invention also provides a sachet prepared by the method as hereinbefore described.

A preferred sachet of the invention is water dispersible.

The films of the present invention have a high dispersibility in warm water. This means that they can be used as a packaging material for a product that creates zero waste during end use of the product. For example, the films of the present invention could be used to package a detergent such that during the washing process the film will disperse in water to release the detergent. Alternatively, the films of the present invention could be used to package a foodstuff such that during the cooking process the film will disperse in water to release the foodstuff.

According to the invention, the water dispersibility of the films is assessed using 0.75g samples of each of the final films, conditioned at 55% relative humidity and a temperature of 20°C. Samples are mixed at room temperature using an overhead stirrer at 300 rpm in 300 ml of both reverse osmosis water at 20°C and freshly boiled reverse osmosis water (i.e. having a temperature range 75°C to 90°C) in a 600 ml beaker for 3 minutes. The end mix is visually inspected for any remaining particles, and their size used to judge water dispersibility on the following scale: Very low - majority of particles >30mm; Low - majority of particles ~20-30mm; Average - majority of particles ~10- 20mm; High - majority of particles ~1-10mm; Very high - majority of particles <1 mm; Maximum - no visible particles. Advantageously, the residue is fully biodegradable meaning that the films do not have a negative impact on the environment.

The present invention also provides the use of a film as hereinbefore described to enclose a product and/or to prepare a sachet.

The present invention also provides a method of releasing a product enclosed in a film as hereinbefore described, comprising the steps of:

(ii) allowing the film to disperse, thereby releasing the product.

In preferred methods of the present invention, in step (i) the enclosed product is placed in water at a temperature of at least 50 °C, more preferably in water at a temperature of at least 60 °C.

In a preferred method of the invention, the product is released in step (ii) during a cooking process.

In an alternative preferred method of the invention, the product is released in step (ii) during a washing process.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1a is a photograph of the sachet prepared in Example 10.

Figure 1b is a photograph of the sachet prepared in Example 10 immediately after being placed in a beaker of water at 60°C.

Figures 1c-f are a series of photographs of the sachet prepared in Example 10 at 1 minute, 2 minutes, 3 minutes and 5 minutes, respectively, after being placed in the beaker of water at 60°C.

EXAMPLES

Materials

Kappa-carrageenan was purchased from Tokyo Chemical Industries (TCI), Japan.

Tapioca starch (STT-358 Tapioca Starch Alpha - Instant), potato starch (pregelled), maize starch and rice starch were purchased from BakeRite. Food-grade glycerol (APC Pure) and potato starch (hot soluble) were purchased from APC.

Polysorbate 80 and maize amylopectin (starch from corn) from Sigma-Aldrich Co. Pullulan was purchased from Rongsheng Biotechnology Co. Ltd.

Maltodextrin was purchased from Sigma-Aldrich Co.

Oleic Acid and sorbitol were purchased from Thermo Fisher Scientific.

Tesco Non-Biological liquid laundry detergent capsules were purchased from Tesco Supermarkets, UK.

In this specification, including the Examples that follow, all references to “ambient temperature” or to “room temperature” are to a temperature of approximately 20 to 25°C.

Example 1 (comparative): Preparation of carrageenan monolayer

A kappa-carrageenan monolayer was prepared according to the following steps:

1 . Preparation of an oil-in-water emulsion: Weigh 3.25 g of oleic acid and 1 ,60g of polysorbate 80 and mix them with 20mL of reverse osmosis (RO) water in a 50mL Falcon tube. Sonicate them for 5 min at 50% amplitude, 1 sec on and 0.2 sec off intervals using a Bandelin Sonoplus sonicator (TS113 probe).

2. While cooling down the emulsion, weigh 996.2g of reverse osmosis (RO) water, 6.67g of glycerol, 6.67g of sorbitol in a 2L plastic beaker. Mix well with a spatula. Add 4.73 g of the cooled down emulsion into the plasticiser-water mix.

3. Transfer the mixture to a Karlstein GrandPrix food processor, and add 20g of kappa carrageenan.

4. Mix them at speed 7 at 30 °C for 30 minutes.

5. Move the mixed formulation to the speed mixer container and degas it for 5 minutes at 1950rpm at 3 mbar.

6. Immediately cast the solution after speed mixing to a wet thickness of 2250 pm, using a RK Print K303S multi coater at speed 3 with a doctor blade.

7. The film was then dried for 3 hours at 80°C and then at room temperature overnight.

The monolayer film was obtained by peeling the dry film from the substrate.

Example 2 (comparative): Preparation of starch monolayer

A starch monolayer was prepared according to the following steps: 1. Weigh 500g of reverse osmosis (RO) water, 10.7g of glycerol, 10.7 g of sorbitol in a 1 L plastic beaker. Mix well using a spatula.

2. Transfer the solution to a Karlstein GrandPrix food processor and add 50g of tapioca starch.

3. Mix at speed 4, 85 °C for 45 minutes.

4. Transfer the mixture to the speed mixer container and degas it for 5 minutes at 1950 rpm at 3 mbar.

5. Cast the solution while it is still warm to a 1200 pm wet thickness using a RK Print K303S multi coater at speed 2 using a doctor blade.

6. The film was then dried at 80 °C for 45 minutes in an oven.

The monolayer film was obtained by peeling the dry film from the substrate.

Example 3: Determination of onset melting temperature and sealing strength for polysaccharide monolayers

(i) Preparation of polysaccharide monolayers

10.0g of polysaccharide was dispersed in 100 ml of deionised water at ambient temperature, in a 250 ml flask by overhead stirring. 4.29g of glycerol was then added and the suspension stirred. The suspension was then sonicated using a Bandelin Sonoplus sonicator (TS113 probe) for 10 minutes at an amplitude of 95%, with a cycle of 1 second on, 0.2 seconds off. The solution was then placed in a sonicator bath for 1 min at 80 °C to remove any bubbles.

20 ml of the solution was poured into a 50 ml Falcon tube. The solution was then further degassed by removing large bubbles with a pipette, before being allowed to cool to 55 °C and poured onto a flat glass plate having a Mylar® surface. The liquid was spread out uniformly using a doctor blade to give a wet film of approximately 400 microns thickness. The plate was then put in the oven for 50 minutes at 80 °C to dry the layer of film.

(ii) Measurement of onset melting temperature by Differential Scanning Calorimetry (DSC)

The films produced in step (i) were conditioned overnight at 55% relative humidity and 20°C. The onset melting temperature is a function of the whole film composition including moisture level. A small test sample (10-20mg) was cut from each film and accurately weighed. Each sample was placed in 40 pL aluminium pans (#51119870, purchased from Mettler Toledo), and heated from 25°C to 160°C at a heating rate of 10°C/min in a nitrogen atmosphere using a DSC822e from Mettler Toledo. The pan lid was pierced using a 50pm diameter needle prior to the sealing. An empty pan was used as a reference. The normalised heat flow was recorded and plotted as a function of temperature.

The onset melting temperature of a sample is defined as the first inflection point in the DSC curve showing a rate increase in the heat flow to the sample with increasing temperature. As the sample starts to melt, the heat flow to the sample increases, thus creating a change of gradient and an inflection point in the graph.

Normalised heat flow plots can be visually assessed by an operator to determine the inflection point in the graph. However, this analysis is now typically done using software analysis tools. Such analysis tools are typically included as part of the equipment operating system. Suitable software includes the STARe evaluation software supplied by Mettler-Toledo.

Data from the normalised DSC plots obtained above was analysed using the STARe evaluation software version 16.30 to determine onset melting temperatures. Results are shown in Table 1 below. The thermal properties of a starch mixture are a complex combination of the relative ratio of amylose to amylopectin in the starch, prior thermal treatments and the level and nature of other ingredients.

Table 1

(iii) Determination of sealing strength Test samples of some of the layers produced in step (i) were prepared and subjected to a seal strength measurement. Test samples of width 25 mm were cut to the dimensions given in ASTM F88/F88M-15 and conditioned overnight at 55% RH and 20°C. Test strip samples were then sealed using an RDM heat sealer to give a fin seal where two inner surfaces of the film are sealed together (also known as a “fold-over seam”. A lap seal (also known as "overlap seam") is where the outer surface of the film is sealed together with the inner surface of the film. Sealed test specimens were tested using technique A (unsupported) in a Tinius Olsen 5ST tensile tester. A sealing temperature of 100 °C and a dwell time of 1 second were employed. The results are shown in Table 2 below.

Table 2

As demonstrated above, the onset melting temperature of a material relates inversely to its ability to form a strong seal. For example, the STT-based layer has a lower onset melting temperature and forms a strong seal. The BPS-based layer has a higher onset melting temperature and forms a good seal, but this is not as strong as the STT-based seal.

A lower onset melting temperature for the plant-derived polysaccharide/fungi- derived polysaccharide/agar-containing layer of the bilayer films of the present invention is advantageous for multiple reasons. Not only has it been demonstrated that a stronger seal strength can be achieved, but a lower onset melting temperature means that a lower temperature needs to be applied to the outer red algae-derived polysaccharide containing layer of the bilayer films of the present invention in order to result in effective sealing of the inner plant-derived polysaccharide/fungi-derived polysaccharide/agar- containing layer. This means that the film degradation (e.g. as a result of burning) is avoided, and also that shorter dwell times are required to form the seal, making the sealing process more industrially viable.

Example 4: Preparation of carrageenan - starch bilayer film (i) Preparation of carrageenan mixture

1 . Preparation of an oil-in-water emulsion: Weigh 3.25 g of oleic acid and 1 ,60g of Polysorbate 80 and mix them with 20mL of water in a 50mL Falcon tube. Sonicate them for 5 min at 50% amplitude, 1 sec on and 0.2 sec off intervals using a Bandelin Sonoplus sonicator (TS113 probe).

2. While cooling down the emulsion, weigh 996.2g of reverse osmosis (RO) water, 6.67g of glycerol, 6.67g of sorbitol in a 2L plastic beaker. Mix well with a spatula.

3. Add 4.73 g of the cooled down emulsion into the plasticiser-water mix.

4. Transfer the mixture to a Karlestein GrandPrix food processor, and add 20g of kappa-carrageenan

5. Mix at speed 7 at 30 °C for 30 minutes.

(ii) Film formation - carrageenan layer

6. Move the mixed formulation to the speed mixer container and degas it for 5 min at 1950rpm at 3 mbar.

7. Immediately cast the solution after speed mixing to a wet thickness of 1700 pm, using a RK Print K303S multi coater at speed 2using a doctor blade.

8. The film was then dried in the oven at 80 °C for 3 hours.

(iii) Preparation of starch mixture

1. Weigh 500g of RO water, 10.7g of glycerol, 10.7 g of sorbitol in a 1 L plastic beaker. Mix well using a spatula.

2. Transfer the solution to a Karlstein GrandPrix food processor, and add 50g of tapioca starch.

3. Mix at speed 4, 85 °C for 45 minutes.

(iv) Film formation - starch layer

4. Transfer the mixture to the speed mixer container and degas it for 5 min at 1950 rpm at 3 mbar.

5. Cast the solution onto the kappa-carrageenan layer to a 300 pm wet thickness using a doctor blade, speed 2.

6. The film was then dried at 80 °C for 30 minutes in an oven. The bilayer film was obtained by peeling the dry film from the substrate.

Example 5 (comparative): Preparation of carrageenan/starch monolayer

1 . Prepare a carrageenan solution and a starch solution as described in Example 1 and Example 2, respectively.

2. Mix together 150 mL of the starch solution and 850 mL of the carrageenan solution.

3. Transfer the mixture of starch and carrageenan solution to a Karlstein GrandPrix food processor and mix for 15 minutes at 30 °C at speed 4.

4. Immediately cast the solution after speed mixing to a wet thickness of 2000 pm, using a RK Print K303S multi coater at speed 2, using a doctor blade.

5. The film was dried in an oven at 80 °C for 3 hours.

The monolayer film was obtained by peeling the dry film from the substrate.

Example 6: Measurement of film tensile strength and elongation

Measurement of film tensile strength and elongation was tested according to ASTM D882. Rectangular test samples of length 80mm and width 10 mm were cut (which falls within the described specifications in ASTM D882) and conditioned overnight at 55% RH and 20°C. The test samples were tested using a Tinius Olsen 5ST tensile tester with flat grip inserts, an initial grip separation of 50mm and a testing speed of 50mm/min (strain rate of 1mm/mm*min).

Utmost care was exercised in cutting specimens to prevent nicks and tears that cause premature failures and ensure repetitive sample quality.

The results are shown in Table 3 below. Tensile strength was reported in MPa and elongation at break in %.

Table 3

The carrageenan film of Example 1 has very good tensile strength and elongation making it a useful film for packaging applications. However the starch film of Example 2 has a very low tensile strength and a high elongation making it too weak to be useful. When the two materials are combined, the resulting films of Examples 4 and 5 have good tensile strength and elongation as a blend or as a bilayer making them useful films for packaging applications.

The results demonstrate that the bilayer films of the present invention have a good mechanical properties and are not prone to breaking or cracking under elongation strain.

Example 7: Measurement of seal strength

Test samples of width 25 mm were cut to the dimensions given in ASTM F88/F88M-15 and conditioned overnight at 55% relative humidity and 20°C. Test strip samples were then sealed using an RDM heat sealer to give a fin seal where two inner surfaces of the film are sealed together (also known as a “fold-over seam”), or a lap seal (also known as "overlap seam") where the outer surface of the film is sealed together with the inner surface of the film. Sealed test specimens were tested using technique A (unsupported) in a Tinius Olsen 5ST tensile tester. A sealing temperature of 140 °C and a dwell time of 1 second and pressure of 3 bar were employed. The results are shown in Table 4 below. Each example was tested in triplicate. For each example, the table below presents the average of the heat sealing maximum force. The maximum force encountered as three samples of each specimen was stressed to failure and the average of three samples was reported as Newtons/meter (N/m). For the film of Example 4, two seal types were tested: a fin seal where two starch surfaces were sealed together (“starch-starch seal”) and a lap seal where a starch surface was sealed to a carrageenan surface (“starch-carrageenan seal”).

Table 4

The results show that the carrageenan film of Example 1 does not seal at all, whilst the starch film of Example 2 has a high seal strength. When the two materials are combined into a blend (as in Example 5), the properties of the starch are not present in the resulting film and it has a low seal strength and therefore is not suitable for forming closed packaging such as sachets. If the two materials are formed into a bilayer (as in Example 4), a high seal strength is achieved. As shown for Example 4, the highest seal strength is achieved with a starch-starch seal. A lower but still very good seal strength is achieved with a starch-carrageenan seal. The results demonstrate that the bilayer films of the present invention can have very good seal strengths.

The carrageenan/starch bilayer of Example 4 (having a film thickness of 69pm, and conditioned and stored at 55% relative humidity and a temperature of 20°C) was taken on for further seal strength testing of the starch-starch fin seal, at different seal temperatures and a dwell time of 1 second with a pressure of 3 bar. The results are shown in Table 5 below.

Table 5

The results show that for a bilayer film of the present invention, there is an ideal temperature range to obtain an effective seal strength. At low temperatures the seal strength is too low and at very high temperatures seal strength starts to drop. Example 8: Measurement of water dispersibility

The water dispersibility of the films of Examples 1 , 2, 4 and 5 was assessed using 0.75g samples of each of the final films, conditioned at 55% relative humidity and a temperature of 20°C. Samples were mixed at room temperature using an overhead stirrer at 300 rpm in 300 ml of both reverse osmosis water at 20°C and freshly boiled reverse osmosis water (i.e. having a temperature range 75°C to 90°C) in a 600 ml beaker for 3 minutes.

The end mix was visually inspected for any remaining particles, and their size used to judge water dispersibility on the following scale: Not dispersible - remains as one film; Very low - majority of particles >30mm; Low - majority of particles ~20-30mm; Average - majority of particles ~10-20mm; High - majority of particles ~1-10mm; Very high - majority of particles <1mm; Maximum - no visible particles.

The results of all these tests are shown in Table 6 below.

Table 6

The starch monolayer films of Example 2 were highly dispersible in both room temperature and freshly boiled water.

The films containing carrageenan were not dispersible at room temperature whether as a monolayer in Example 1 , or as mixture in Example 5 or as a bilayer in Example 4.

In freshly boiled water the carrageenan only film of Example 1 was highly dispersible resulting in no visible particles. The films containing starch were highly dispersible in freshly boiled water whether as a monolayer in Example 2, or as mixture in Example 5 or as a bilayer in Example 4. This demonstrates that the films of the present invention can be used to prepare sachets that are insoluble at low water temperatures and maintain their integrity in the presence of water, but that are highly soluble at higher water temperatures.

Example 9: Moisture content of films

The moisture content of various films prepared in the above examples was measured using an Ohaus MB23 moisture analyser, wherein the film samples had first been conditioned at 55% relative humidity and a temperature of 20°C. The results are shown in Table 7 below.

Table 7

Example 10: Dispersion of laundry detergent sachet

Sachets were produced using the bilayer film of Example 4, by heat sealing a starch-starch fin seal along the length and ends of the film with an RS PRO heat sealer on power 2. The sealed sachets contained a concentrated laundry liquid detergent obtained from Tesco non-biological liquid laundry pods as shown in Figure 1a.

The sachets could be easily handled and maintained their integrity. When added to 250 ml of water at either 40°C, 50°C or 60°C in a 400 ml beaker and stirred at -340 rpm with a magnetic stirrer, the sachets disintegrated and fully released their contents after 5 minutes or less. The higher the temperature the faster the release and at 60°C release occurred in about 1 to 2 minutes as shown in Figures 1 b-f.

This example demonstrates one of the multiple uses of the bilayer films of the present invention, namely to prepare heat-sealed sachets to provide a single dose of laundry liquid detergent. The sachets can be safely handled by the consumer and will release the detergent on contact with warm water in the washing machine.

Claims

CLAIMS:

1. A film comprising: a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers; and a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers.

2. A film as claimed in claim 1 , wherein the film has a thickness of between 20 pm and 120 pm, preferably between 30 pm to 100 pm.

3. A film as claimed in claim 1 , wherein the at least one red algae-derived polysaccharide in the first layer is carrageenan, preferably iota-carrageenan, kappa-carrageenan or lambda-carrageenan, more preferably kappa- carrageenan.

4. A film as claimed in any one of claims 1 to 3, wherein the film comprises based upon the total weight of the film 3-90 wt.-%, preferably 15-85 wt.-%, more preferably 25-80 wt.-%, most preferably 35-70 wt.-%, of red algae-derived polysaccharides selected from carrageenan, furcellaran, and mixtures thereof determined according to the method described in Glueck et al., 1980, Zeitschrift fur Lebensmittel-Untersuchung und -Forschung, 170, 272-279.

5. A film as claimed in any one of claims 1 to 4, wherein the film has a heat sealing strength of at least 40 N/m, preferably at least 60 N/m, more preferably at least 80 N/m, even more preferably at least 100 N/m, most preferably at least 120 N/m, as measured by ASTM F88/F88M-15 at 55% relative humidity and 20 °C after the film has been conditioned at 55 % relative humidity and at 20 °C for at least one hour and then sealed as either a fin seal or a lap seal at a temperature of 140 °C and a pressure of between 1 and 3 bar applied for a time of 1 second.

6. A film as claimed in any one of claims 1 to 5, wherein the organic plasticiser in the first layer is selected from glycerol, diglycerin, dipropylene glycol, tetraethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, trimethyl propane, poly ether polyols, 2-methyl-1 ,3-propanediol, ethanolamines, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, oleic acid, monoglycerides, diglycerides, triglycerides, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids, lactic acid, citric acid, glycolic acid, malic acid, tartaric acid, gluconic acid and mixtures thereof, preferably a mixture of glycerol, sorbitol and oleic acid.

7. A film as claimed in any one of claims 1 to 6, wherein the organic plasticiser in the second layer is selected from glycerol, diglycerin, polyethylene glycol, propylene glycol, dipropylene glycol, tetraethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, trimethyl propane, poly ether polyols, 2-methyl-1 ,3-propanediol, ethanolamines, sorbitol, mannitol, xylitol, triethyl citrate, oleic acid, monoglycerides, diglycerides, triglycerides, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids, lactic acid, citric acid, glycolic acid, malic acid, tartaric acid, gluconic acid and mixtures thereof, preferably a mixture of glycerol and sorbitol.

8. A film as claimed in any one of claims 1 to 7, wherein the film is more than 75 %, preferably more than 80 %, more preferably more than 85 %, even more preferably more than 90 %, most preferably more than 95 % biodegradable, in fresh water according to ISO 14851 (2019) after 28 days testing.

9. A film as claimed in any one of claims 1 to 8, wherein the film is more than 75 %, preferably more than 80 %, more preferably more than 85 %, even more preferably more than 90 %, most preferably more than 95 % biodegradable, in marine water according to ASTM D6691 after 28 days testing.

10. A process for preparing a film as claimed in any one of claims 1 to 9, comprising the steps of:

(i) providing a first layer comprising based on the total weight of the first layer: at least 20 wt.-% of at least one red algae-derived polysaccharide selected from carrageenan, furcellaran, and mixtures thereof, and at least 5 wt.-% of one or more organic plasticisers; (ii) providing a second layer comprising based on the total weight of the second layer: at least one material selected from plant-derived polysaccharides, wherein said plant-derived polysaccharide is a starch, fungi-derived polysaccharides, wherein said fungi-derived polysaccharide is pullulan, and agar, and at least 5 wt.-% of one or more organic plasticisers; and

(iii) forming said first layer and said second layer into said film.

11. A film obtained by or obtainable by a process as described in claim 10.

12. A product enclosed by a film according to any one of claims 1 to 9 and 11 .

13. A method of enclosing a product, comprising the steps of:

(i) wrapping the product in a film as claimed in any one of claims 1 to 9 and 11 ; and

(ii) heat sealing the film around the product to form a sachet.

14. A method as claimed in claim 13, wherein the duration of step (ii) is less than 2 seconds, more preferably less than 1 second, more preferably less than 0.5 seconds, and wherein step (ii) is conducted at a temperature of less than 160 °C, preferably less than 140 °C, preferably less than 120 °C.

15. A sachet prepared by the method of claim 13 or claim 14.

16. Use of a film as claimed in any one of claims 1 to 9 and 11 to enclose a product and/or to prepare a sachet.

17. A method of releasing a product enclosed in a film as claimed in any one of claims 1 to 9 and 11 , comprising the steps of:

(ii) allowing the film to disperse, thereby releasing the product.

18. A method as claimed in claim 17, wherein in step (i) the enclosed product is placed in water at a temperature of at least 50 °C, more preferably in water at a temperature of at least 60 °C.