Thin film

Abstract

The present invention provides a decal or sticker configured to be applied to a surface, wherein the decal or sticker is cut form a sheet of biopolymer thin film. The biopolymer thin film can comprise a polysaccharide in the form of agar and a polymer of amino acids in the form of gelatine. The biopolymer thin film can further comprise a glycerine plasticiser.

Description

[0001] Thin Film

[0002] This document claims priority to AU2024900061 entitled “thin film”, filed on 10

[0003] January 2024, the entire content of which are hereby incorporated by reference.

[0004] Technical field

[0005] The present invention relates to non-petrochemical plastics such as biopolymers. In an embodiment, the biopolymer is made into a thin film. The thin film can be used as a decal or sticker applied onto a surface such as a wall, glass or metal.

[0006] Background

[0007] Polyvinyl Chloride or PVC is a versatile material widely employed across various industries due to its desirable properties. Its applications span from construction materials and piping to clothing, bags, and inflatable structures.

[0008] Whilst prevalent, PVC plastics pose significant environmental and health concerns throughout their lifecycle. The production of PVC relies on the extraction of petroleum, a finite resource tied to geopolitical conflicts and environmental degradation. Communities near PVC production facilities experience elevated cancer rates, highlighting the human cost of this manufacturing process.

[0009] During use, PVC releases volatile organic compounds, including chloride gas and formaldehyde, known carcinogens harmful to human health. This off-gassing also poses a threat to objects. For example, some museums and galleries prohibit PVC use near valuable collections due to the potential for degradation.

[0010] Once used, PVC becomes a part of the waste stream. PVC incorporates plasticisers, hindering its recyclability. Disposal options are limited, often resulting in landfill, incineration, or the release of harmful waste into waterways, negatively impacting marine life. The persistent nature of these petrochemical plastics exacerbates environmental pollution, as they do not readily biodegrade. Those concerned about the detrimental effects of PVC advocate for environmentally friendlier alternatives. These advocates are pushing for materials that are not only safer for human health but also more sustainable, addressing the environmental challenges posed by traditional petrochemical plastics. The search for a kinder alternative reflects a broader commitment to fostering a healthier, more sustainable future.

[0011] One alternative to PVC is a biopolymeric plastic derived from a naturally occurring polymer such as a biopolymer. Biopolymers have found use in the food packaging industry where the toxic effects of e.g. a PVC wrapper are most undesirable. Food packaging is typically flexible and versatile.

[0012] While biopolymer plastics are an advantageous alternative in the food packaging industry, their application into other areas where PVC is used is not yet fully adopted. This is in part due to the challenges faced with working with biopolymer materials which do not have the same properties as their synthetic counterparts. It is an aim of the present invention to provide a new use of a biopolymer plastic, or at least to provide an improved form of an existing use of a biopolymer plastic, by disclosing a new method for working with biopolymer that in embodiments allows for the formation of new, improved and or more sustainable products.

[0013] Summary of invention

[0014] In a first aspect there is provided a decal or sticker configured to be applied to a surface, wherein the decal or sticker is formed from a biopolymer thin film. In an embodiment, the decal or sticker configured to be applied to a surface, is cut from a sheet of biopolymer thin film.

[0015] In an embodiment the biopolymer thin film comprises a polysaccharide in the form of agar, and a polymer of amino acids in the form of gelatine. The biopolymers can be used together with glycerine which acts as a plasticiser for the thin film.

[0016] The thin film stickers or decals can be used as e.g. branding, decoration, removable protective coverings, safety markings, privacy screens or information displays. As a thin layer of material, optionally with an adhesive backing, the decals can be easily affixed to surfaces such as glass, metal or plastic. The decals can serve as versatile tools for conveying messages, promoting products, protecting surfaces, visibly marking transparent screens for safety purposes, adding privacy or enhancing aesthetics.

[0017] In a second aspect there is provided a method for forming a decal or sticker from a biopolymer, the method comprising the steps of mixing, under heating, one or more biopolymers into water or a substantially aqueous liquid to form a mixture; optionally adding a plasticiser to the mixture; wherein the mixture is heated until the mixture becomes substantially optically translucent; causing a thin film of the mixture to set over a surface having a boundary to contain the mixture, the thin film of mixture having a first side in contact with the surface and a second side exposed to air; heating the second side to dissipate any air bubbles; allowing the thin film to set; once set, releasing the thin film from contact with the boundary; drying the thin film; once dried, cutting the thin film to remove edge defects; and peeling the cut thin film from the surface to provide a decal or sticker formed from a biopolymer.

[0018] In an embodiment the biopolymer comprises a polysaccharide in the form of agar, and a polymer of amino acids in the form of gelatine. A glycerine plasticiser can be added to the mixture.

[0019] PVC is presently the most commercially used form of thin adhesive film in stickers or decals for advertising on e.g. windows. The flexibility and durability inherent in PVC make it an attractive choice for such applications, offering a cost-effective solution for businesses aiming to visually showcase their products and promotions. Globally, the consumption of PVC thin film for advertising purposes is substantial, given its widespread use in the marketing and retail sectors. Within the context of artistic endeavours, the prevalent use of PVC in decal applications for exhibition purposes has become a focal point of concern. Acknowledging the environmental implications associated with PVC, a shift in material sourcing is considered to be an imperative. Based on the teaching herein, algae-based biopolymeric plastics such as those in the present invention can now be a viable substitute for conventional petrochemical plastics in decal production. This strategic move to biopolymers in decal production is aligned with the broader goal of integrating sustainable materials into artistic practices, addressing environmental impact through conscientious material selection.

[0020] In the present invention, the inventor has found that a biopolymer film can be prepared using the herein described process and then used in place of most PVC. The present thin film is a non-petrochemical plastic film. The present film is PVC free. In an embodiment, the present thin film can be used as a replacement for petrochemical-based plastic films used with adhesives for application.

[0021] A key development in this process, therefore, lies in the ability to produce thin-film biopolymer sheets at scale with a finish that is substantially visually and substantially functionally identical to traditional PVC, while remaining compatible with existing industrial machinery and skills. This helps to ensure that professionals in the field can adopt the material seamlessly, without requiring additional training or equipment modifications. The biopolymer sheets of thin film are typically created with a smooth, glossy surface having a consistent texture, and uniform thickness, which is considered essential for use with plotters, flatbed printers, and other standard equipment.

[0022] Achieving a substitute involves control over the formulation, handling of the sheets, production environment, and curing processes. The material is engineered to replicate to the extent possible the opacity, durability, and flexibility of PVC, making it suitable for a wide range of applications, from signage to decorative films. Advanced pigment integration techniques and an optimised production workflow can further enhance the sheets' commercial viability and aesthetic appeal. This can, in embodiments, represent a sustainable alternative to PVC that aligns with industry standards while addressing environmental concerns, paving the way for broader adoption in industrial and artistic applications.

[0023] Scaling up the production of biopolymeric film from small-scale laboratory samples to large-scale, consistent sheets represents a significant technological development. At a small scale, the production of biopolymeric films is typically confined to controlled environments, such as petri dishes as moulds, where variables such as composition, curing conditions, and dimensional consistency are easily managed. However, transitioning from these controlled conditions to producing uniform, large-scale sheets suitable for commercial applications introduces numerous complexities. The material’s natural properties, including significant shrinkage during drying, amplify the challenges, as variations in mixture composition, gel structure, or additive distribution can readily result in defects such as cracks, tearing or apertures in the finished sheet that are incompatible with use at an industrial scale or with existing commercial machining equipment.

[0024] The process of scaling the sheet size requires standardisation to ensure that the material can be produced at a size and quality suitable for industrial applications. This involves creating sheets large enough to be rolled onto rolls for transport and that allows the material to be fed seamlessly into plotters or other industrial machines. These machines are used for the production of artistic designs or other applications that demand precision and consistency. The material should maintain uniform thickness, texture and mechanical properties across its entire length to ensure compatibility with such machinery and to achieve reliable performance during processing and cutting. Achieving this involves overcoming the sensitivity of the material to environmental variables such as timing of material cooking, pouring, setting, drying temperature, humidity, airflow and curing time, all of which must be monitored and controlled as described herein.

[0025] The handling of the material post-production is also a challenge. Removing large- scale sheets from moulds without damaging their integrity, ensuring they can be stored and transported without deformation, and enabling their use in existing industrial machinery for cutting, printing, and installation are all critical advancements. Moreover, developing methods for applying, deinstalling, and recycling the material at scale helps to ensure its usability across a wide range of applications, from artistic to commercial, while maintaining its sustainability. This scaling-up process transforms a promising laboratory concept into a commercially viable material, capable in embodiments of addressing real-world demands with consistent quality and performance.

[0026] Brief Description of the Figures

[0027] Embodiments of the invention will now be described with reference to the accompanying drawings which are not drawn to scale and which are exemplary only and in which:

[0028] Figures 1 and 2 are exemplary sticker decals attached to a shop front window.

[0029] Figures 3 shows the application of water in a non-adhesive application of an exemplary biopolymeric decal to a glass surface.

[0030] Figure 4 shows the squeegee application of an exemplary decal with no adhesive. In this embodiment, bubbled texture to the sheet was designed as an artistic detail.

[0031] Detailed Description of Embodiments of the Invention

[0032] The present thin film is formed from one or more organic polymers or biopolymers.

[0033] The organic polymer or biopolymer is naturally occurring. Naturally occurring organic polymers constitute a distinct group of compounds sourced from nature. Unlike synthetic counterparts produced through chemical synthesis, these natural polymers are not artificially engineered.

[0034] In preferred embodiments, the present thin film is free from polymers derived from petrochemicals. Each of the polymers that are used in the film can be renewable and be able to be sourced in ways that are considerably less environmentally destructive than petroleum. The ingredients are preferably far less toxic than existing products, with no known carcinogenic impacts. In embodiments, the safety of each of the base materials is supported by the notion that each of the base ingredients can be edible.

[0035] The naturally occurring organic biopolymer can be a polysaccharide. Polysaccharides are complex carbohydrates composed of multiple sugar units (monosaccharides) linked together. Starch is an example of a polysaccharide made up of glucose molecules linked together by glycosidic bonds. Starch is stored as a form of energy in plants and is a major component of the human diet, found in foods like potatoes, rice, wheat, and corn. Another example of a suitable polysaccharide for use in the present thin film is agar (sometimes referred to as agar-agar). Agar is composed of a variety of polysaccharides, primarily agarose and agaropectin. The main component, agarose, consists of repeating units of agarobiose. Agar is a jelly-like substance obtained from the cell walls of some species of red algae, primarily from "ogonori" (Gracilaria) and "tengusa" (Gelidiaceae).

[0036] In one embodiment, the one or more naturally occurring organic polymer is made up of amino acid monomers. A suitable naturally occurring organic polymer with amino acids is gelatine. The main amino acids present in gelatine include glycine, proline, and hydroxyproline.

[0037] In an embodiment there is only a polymer made of multiple sugar units. In an embodiment, the only polymer present is a polysaccharide such as agar. In an embodiment there is only a polymer made of multiple amino acid units. In an embodiment, the only polymer is gelatine. In an embodiment there is a polymer made of multiple sugar units and a polymer made of multiple amino acid units. Thus, in an embodiment there is more than one biopolymer comprising a mixture of agar and gelatine.

[0038] The biopolymer used to prepare the present thin film can be provided as dry materials. Where there is a combination of agar and gelatine, the dry base materials include a mix of agar and gelatine. Agar can be used as a fine powder with particle sizes that would typically be less than about 0.3mm or 0.25mm. Gelatine can be coarser with particle sizes would typically be less than about 1 mm. Finer gelatine requires less time to fully integrate into the mix and can result in faster cooking times.

[0039] Agar can also be used in other forms, as can gelatine or other organic polymers such as starches, other algae that can form polymers like alginate or carrageenan, or cellulose can also be used.

[0040] The agar used can be food grade E406 Agar, typically derived from Gracilaria genus of red algae. Agars from the Gelidium genus of red algae, which are more commonly processed into laboratory or bacteriological agars can also be successfully used, though due to the substantially higher price of these higher- grade agars, food grade is most commonly used. Lab grade agar costs substantially more because there is processing and testing that occurs to make sure each batch results in replicable results. Food grade agar does not have this testing or consistency.

[0041] A range of technical agars are available that could allow for some strengths to be built into the resulting thin film material. These strengths include higher gel strength, purity for consistency of results at scale, and higher resistance to temperature. Recipes using these specified technical agars can be used for resistance to higher temperature - which as decals would be used in scenarios where, for example, glazing which decals were applied to reached high temperatures in full sun.

[0042] Optionally, a plasticiser can be added to the naturally occurring organic polymer. In some embodiments, a plasticiser is always required. A plasticiser is a substance added to a material to increase its elasticity, flexibility, pliability and or workability. Common plasticisers include phthalates, adipates, citrates and others. In the present invention, which seeks to avoid any use of harmful or toxic chemicals, the plasticiser, if added, is preferably a naturally occurring organic material and is environmentally-responsible.

[0043] The plasticiser can be selected from one or more of glycerine, honey, agave syrup or other similar material. In an embodiment, the plasticiser is glycerol. A vegetable glycerine (glycerol plasticiser) is hygroscopic, meaning it attracts and retains water molecules. This property can help to maintain moisture in the thin film materials, preventing it from becoming dry and brittle. It is also possible that the addition of gelatine in the material aids in the outcome of a decal that is superior in its ability to “stick”, which can be important for the development of decals that are adhered to surfaces without the use of a petrochemical adhesive layer.

[0044] The agar can be added in an amount in the range of from about 0.5 wt% to about 7 wt%, preferably about 1 wt% to about 6 wt% of the overall weight of the composition including water.

[0045] Gelatine can be added in an amount in the range of from about 0.2 wt% to about 6 wt%, preferably about 0.3 wt% to about 5 wt% of the overall weight of the composition including water.

[0046] The ratio of agar to gelatine can be in the range of from about 0.3 to about 3, preferably about 0.3 to about 1 .5, more preferably about 1 to about 1 .

[0047] The glycerine, if present, can be added in an amount in the range of from about 0.5 wt% to about 10 wt%, preferably about 1 wt% to about 7 wt% of the overall weight of the composition including water. The ratio of agar to glycerine can be in the range of from about 0.25 to 4, preferably about 0.25 to about 1 .5 more preferably about 1 to about 1 .

[0048] Water typically makes up in the range of from about 80 to about 95 wt% of the composition during preparation.

[0049] By way of example only, the recipe can comprise 380g agar, 380g gelatine, 380g glycerine and about 10L of water then the weight percentage of each component agar, glycerine and gelatine is about 3.4 wt%. Alternatively, as an example, the recipe can comprise 172g agar, 172g gelatine, 212g glycerine and about 7L of water then the weight percentage of each component agar, gelatine and glycerine is about 2.3 wt%, 2.3 wt% and 2.8 wt% respectively. Without wishing to be bound by theory, it is thought that the inclusion of gelatine enhances the material's mechanical strength, providing tear resistance and durability throughout the application process. The cohesive protein matrix is thought to reinforce the structure, making it less prone to fracturing or tearing. Glycerine when present further reduces brittleness, ensuring the material remains easy to handle during installation and removal. This durability and flexibility make the material well-suited for artistic and industrial applications.

[0050] The naturally occurring organic polymer(s) are first dissolved in water or a substantially water-based liquid. The water is heated in in a vessel. The water can be heated until boiling point is reached. The water can be heated to a rolling boil with heat set on induction hot plate to between 120 degrees C and 200 degrees Centigrade (C) (or more).

[0051] The water can be agitated to create a whirlpool into which the naturally occurring organic biopolymer material is added. The temperature of the water can be lowered slightly to below boiling prior to adding the ingredients. The naturally occurring organic polymer can be added gradually to avoid clumping and to ensure the best possible dissolution. Preferably, at least about 95, 99 or 100% of the added naturally occurring organic polymer dissolves in the water. Complete dissolution is preferred so that the resultant thin film is not affected by any undissolved particles. In an embodiment, the mixture can be blended to assist in dissolution. Any type of blender can be used. In an embodiment, an immersion blender is used to achieve a smooth integration of the materials without clumping. The blender can be used in such a way as to reduce bubble formation in the liquid. The blender can be held at an angle such as a 45-degree angle to reduce bubble formation. The blender head can be kept fully submerged to reduce bubbles forming in the liquid mixture. Blending can continue until a smooth consistency of the mixture is achieved.

[0052] Once prepared, the mixture can be left to simmer below boiling point. Preferably the temperature is kept at in the range of from about 60 to about 80 degrees C, so there is no visible simmer in the mix (no bubble creation). A lid is preferably always be in place over the vessel while cooking to minimise evaporation. The mixture can be left to simmer until it begins to exhibit some optical translucency or transparency. This can take about 10, 20 or 30 minutes. The translucency, detectable by the human eye, is thought to come from the bubbles in the mixture dissipating. No visible granules should appear in the mixture under close inspection.

[0053] "Optically translucent" refers to a material or substance that allows light to pass through it. Translucency is a property that lies between transparency (where light passes through completely) and opacity (where light is blocked). In optically translucent materials, while some light is transmitted, it may be scattered or diffused to some extent, making the material not completely transparent but still allowing light to penetrate. In the present formulation, the material is not opaque. Preferably, the material is greater than 80, 85, 90 or 95 % translucent.

[0054] If a plasticiser is present, it can be added at any time. In an embodiment, the plasticiser is added to the water and dissolved prior to the addition of the dry biopolymer(s).

[0055] Pigment can be added optionally once all base ingredients are fully dissolved into the mixture. The pigment is preferably a compostable pigment. The pigment preferably has a light-fast rating to ensure consistent and replica table results that can maintain a compostable material in its final form. Some natural pigments are sensitive to temperature and so are added as close to pouring as possible.

[0056] Typically, pigment would be added as a liquid mix. Dry pigments can be pre-mixed into the water or another liquid solution to be added to the liquid mix and integrated with an immersion mixer. The pigment can be any pigment that is used to dye plastic films. Preferably the pigment is a naturally occurring compound. The pigment can be an algae-derived betacarotene which imparts a temporary orangeyellow colour. Betacarotene is acidic and needs to be used minimally to prevent impacting setting of the polymer.

[0057] Once the mixture is integrated, the consistency should be tested for pouring to ensure that the mix is fluid enough to be poured at a consistent speed. To ensure no clumps or inconsistencies in the mixture, the mixture can be poured through a fine sieve during or before the pouring step. The mixture preferably has a freely pouring consistency. It should be a similar consistency to slightly thickened water e.g. as thick as a syrup. Thicker than liquid water, but thinner than honey. Another way to check is to conduct the pour process described further below. If the mixture does not cover the surface of the tray without setting before the coverage is complete, it is too thick. In this instance, where the mixture has set and is too thick, the set mixture can be left to set, then peeled up and immediately returned to the cooking vessel preferably with additional water. The heating step is then repeated, assuming that the process is resumed from the point the dry ingredients were added. This heating may continue for longer than if using dry ingredients added to liquid water to ensure dissolution. Heating of the mix when re-melting a gel must continue until the mix has returned to the liquid form - aided by intermittent mixing with the immersion blender to break apart the gel into a smooth paste as it heats to a liquid. It may take between 20 and 35 minutes before the mix is returned to a state ready for pouring testing again.

[0058] Making sure the mix is sufficiently thin for pouring also reduces the occurrence of bubbles. Food grade agars can vary in how viscous the final mix is, so this needs to be tested in-situ once the mix is made. If additional water is needed, about 50 to 100 mL of water can be added per each 1500 mL of starting water to achieve an ideal consistency. Water is preferably added at a similar temperature to the mixture to avoid any unwanted shock “setting” of the mixture. Additional liquid can be integrated using a blender such as the immersion blender.

[0059] The thin films are created once the cook is complete. The thin film can be prepared by pouring the molten or hot runny mixture described above over a surface. The thin film will take the shape of the surface including any undulations, so the surface should be selected to have the desired properties of the resultant film. If the resultant film is flat, then the surface should be flat, and so on. The surface could be curved although it will be difficult to get a uniform thickness over a curved surface. The surface can be timber, rubber, ceramic, a petrochemical plastic, metal or glass. A glass surface will provide a glass-textured smooth finish to the sheet. If the decal or sticker will be applied to glass, then a glass surface is prepared since it is more certain that the resultant product will adhere to a glass or other smooth non-porous surface without any adhesive used. The surface can be room temperature during pouring. In some embodiments, the surface can be heated prior to pouring to ensure no setting. The surface can be cooled prior to pouring. The thin film once poured over the surface can level under the influence of gravity.

[0060] The surface can comprise a boundary which provides a stop for the spreading of the liquid. The surface can be the base of a large tray. The boundary can be the edges or walls of the tray. The tray can be formed from a material of any thickness. However, preferably it is thick enough to resist changing shape as the evaporation of moisture from the material causes tension. If a tray material is too thin or flexible, it will buckle and prevent the resultant film from being flat. In an embodiment, the tray is formed from at least about 10 or 12mm form ply.

[0061] The tray can have any dimensions. The tray can have, for example, a base area of 2400mm x 1200mm. The side edges of the tray could be 50mm in height. The base of the tray can be lined with glass to achieve the glass-textured smooth finish on the surface of the finished thin film sheet.

[0062] Any vessel such as a tray into which the mixture is poured is preferably selflevelling or levelable. This will assist in getting a flat film by uniform spread and uniform thickness. The trays can be movable e.g. positioned on tables with castors. Tables and trays can be levelled before the mixture is poured.

[0063] In an embodiment, a table equipped with adjustable jacks for levelling each leg can be used during the production process, where a moulding tray is positioned for pouring. The jacks can be adjusted either manually or mechanically, using a drill as a driver. However, for precise levelling, manual adjustment is recommended to achieve optimal control. Levelling is guided by the use of spirit levels, ensuring the bubble indicator is positioned exactly in the middle of the guide, indicating a high degree of levelness. At least two spirit levels can be placed on the interior of the moulding tray at various points to assess levelness across the entire table surface. These are positioned to check levelness in all directions, including lengthwise and widthwise. For additional accuracy, a digital inclinometer can also be used as a supplementary tool.

[0064] Precise levelling helps to achieve a consistent thickness in the moulded biopolymer sheet during setting. Any unevenness in the table or tray impacts the uniformity of the sheet, leading to variations in thickness that could affect the final quality and performance of the material. Therefore, the table is levelled immediately before pouring, ensuring that the levelness remains intact while the mould is setting. The moulding tray, due to its weight, sits securely on the table without requiring additional support or adjustments. Its stability relies entirely on the table being levelled correctly. By combining manual jack adjustment, spirit levels, and optional digital tools, this method ensures a stable and precise surface for producing high- quality biopolymer sheets.

[0065] The mixture can be poured in a steady, even stream, moving along the tray to achieve maximum coverage while paying attention to edges. The mix can poured out by hand or by machine. The mixture can be poured at an average rate of at least about 500ml to about 5 L per second.

[0066] There can be a first pour step and a second pour step. The pour rate in the first step can be faster than the pour rate of the second step. Overall, the pour can take less than about 90, 60 or 45 seconds, to avoid setting of the mixture during pour. Preferably, the average rate of pouring will be in the range of from about 3L to about 5L per second, such as at least about 3L per second, at least about 4L per second or at least about 5L per second. The choreography of the pour will aim to cover the entire tray in the least amount of time, while avoiding spillage over the sides of the mould. The velocity and placement of the pour(s) will achieve this by first beginning with a first pour rate at the middle of e.g. a short edge of the mould. The first pour rate can be in the range of from about 7L to about 9L per second, with force behind it to spread the mixture across the mould in the direction of a longitudinal axis (or lengthways) in the mould, enabling a coverage of the mould of up to about 70 or 80%. Following this first pour, the edges of the mould free from mixture can be filled in with additional lower velocity pours at a rate in the range of from about 3L to about 6L per second, with lowered force behind them, until the entire mould is covered. For a tray mould that is about 1200mm x 2400mm, about 14L to about 16L of mixture may be required to form the fill of the film in the mould. This will make a wet mixture layer having a height in the range of from about 4mm to 5mm. For a 1200mm x 2400mm sized mould with a poured depth of 4mm, the pour as described herein should take about 30 to 50 seconds, such as about 40 seconds.

[0067] The tray can be adjusted to direct the flow during pouring i.e. to spread the mixture in the tray. The mixture can be applied to any part of the tray to ensure coverage. The process can be performed to ensure that the tray fills whilst the mixture remains within the temperature range of about 60 to about 80 degrees. At these temperatures the mixture is in a liquid state. Heating the tray can assist in maintaining the liquid state.

[0068] Preferably, the mixture is poured so that there is a cover of fresh liquid over as much of the tray as possible to keep the mix cooling in a uniform way across the whole sheet and until entire mix is poured onto sheet and entire tray is covered.

[0069] In some embodiments, it might be desirable for some cooling to occur in parts of the sheet and not others. This might provide an artistic effect. The pouring method can be manipulated to achieve varied cooling resulting in edges and patterning throughout the sheet.

[0070] The sheet that is formed can cool at ambient room temperature. The first side of the sheet can be in contact with the bottom of the tray. The second side is exposed to air if uncovered. The second side can dry with natural inclusions from the process of making the sheet. These natural inclusions can result from bubble outlies from production. There can be slight variations in thickness across the whole sheet. These can be manually manipulated to eliminate bubbles or other imperfections, or these can be left as an artistic / design effect.

[0071] Following pouring, a heat gun can be used to remove any bubbles from the exposed second surface. Bubbles are ideally removed as soon as possible, while mix is still in hot liquid form. In this state, when bubbles are popped, the liquid fills the gap, and no lasting mark appears in the surface of the sheet once dry. If bubbles remain in the sheet for drying, small apertures can form where the bubble of air causes pressure in the material as water evaporates rapidly from the sheet as it dries. An 18V heat gun can be used with a 4.0Ah, 2.0Ah or 2.5Ah. The heat can be applied to the exposed surface of the thin film. Higher powered heat guns can also be used, though the additional air pressure in these higher power tools can result in damage to the forming gel so they need more attention to use without causing damage to the setting sheet. In some embodiments, instead of a heat application, a fine spray of solvent over the thin film, such as isopropyl alcohol or methylated spirits can be used to attempt to reduce bubbles in the surface. An alternative way to remove bubbles if they become problematic is to slightly increase the hydration in the initial mix used to form the film which in turn reduces the viscosity. Furthermore, before pouring it can be useful to wait until the mix has the least number of bubbles visually in the liquid before pouring.

[0072] As the thin film dries, there can be shrinkage. When the thin film sets in the tray moulds, this shrinkage happens mostly across the exposed top surface, resulting in a thinner large sheet, rather than a smaller sheet at the same thickness as first poured. The smooth surface of the tray can prevent shrinkage across the plane. This also creates pull across the surface, and bubbles remaining un-popped can lead to an area around the bubble pulling out into a tear with thicker edges around a hole in the finished sheet.

[0073] When poured as a large-scale piece, the mixture is fragile as it cools into a gel. Following pouring, it is important to avoid any movement or knocks to the mixture in the tray as it cools and sets. The time it takes to set varies based on ambient temperature, insulation properties of the tray and the surrounds and volume and mass of the mixture in the tray. The recipe used to form the mixture is also a factor. Mixtures with lower concentration of biopolymer or any acidic components in the added pigment or other additives will form a softer gel that is more fragile.

[0074] In an embodiment, the mixture is cooled at ambient temperature and pressure. In an embodiment, the mixture can be cooled to assist in the setting into a firm gel, stable for movement in the mould. Once the material is set, an incision can be made along the immediate edge of the tray to separate the thin film from the boundary (or tray wall). The cut can be made to the depth of the tray base, through the full layer of gel. This is performed to prevent the sheet from staying adhered to the edge of the tray as it dries and shrinks. Failure to do this can lead to the sheet remaining stuck to the side of the tray at the level it was poured at. As the sheet dries and shrinks across the surface, it becomes lower in the tray as it shrinks in thickness. If not cut, the edges of the sheet will be held up to the pour level and result in the sheet coming away from the tray surface, which impacts the final texture of the finished sheet.

[0075] The gel is preferably dried before bacteria or fungus can grow. The drying is ideally done as soon as possible i.e. within about 48 or about 72h of pouring the film. The thin film can be dried without any equipment e.g. by drying in the sun or other natural method for drying.

[0076] Alternatively, the film can be dried in a dryer or a dehydrator. A dryer can be effective to dry the material in a consistent way no matter the outside weather and allowing for control of temperature and airflow. The dehydrator can have spacing around the drying thin films that allow for airflow and heat distribution. The sheets are more moisture-laden than typical items put into dehydrators. Higher performance will be needed from airflow and hence, reducing empty space in the drying area is critical to creating an indoor model that will be workable.

[0077] Cracks in the sheet may indicate improper cooling before curing, uneven drying conditions, or excessive drying heat. To prevent such issues, in embodiments, drying temperatures should not exceed 50 to 60°C, and consistent environmental conditions can be maintained across the entire sheet during curing.

[0078] The sheets that form are preferably surface defect free as described above. If there is any kind of tear or perforation in the material that has set, and that tear is put under pressure, the tear will propagate and spread rapidly across from the tension point. If there are any surface inconsistencies across the sheet during peeling, the thin film can tear. Peeling uses an amount of tension that would easily rip across an existing fault in the material. To prevent locations of weakness that can result in tears as the sheet is peeled up, a border is cut around the inner sheet, and the outer borders removed before the main sheet is peeled. This is a separate cut to the pre-drying cut.

[0079] To determine the border trim, the edge of each side is assessed for the outer-most point where the main body of the sheet is free of any edge curls, tears or tension points where the edge is still attached to this higher liquid point along the edge (although the pre-drying incision reduces this considerably).

[0080] A measurement is made for a straight line along the edge to separate all of these fault points from the main body of the sheet. This step can make use of two rulers. One long metal one and a smaller ruler that can be of any material. The smaller ruler is used to position the long metal ruler into the position determined, and a sharp, fresh blade of a utility knife is used to cut the material in passes that avoid putting too much pressure on the material. If pressure is too hard, the materials elasticity will cause it to stretch with the blade, deforming the straight line of the cut and dragging the material with the knife.

[0081] Once the cuts are made on each side, the edge material with the faults is pulled up, leaving smooth, straight-cut edges of the material left in the tray. The edge material can be recycled in a repeat of the present method i.e. by dissolving the trim and making new thin film. The remaining cut thin film can be removed from the tray. The smoother the tray-bed, the more challenging the peeling up is at scale, as the smoothness of the material and its natural tack cause it to easily stick back on itself or the tray and can result in accidental tears. As the film is peeled, a nonstick interleaving layer can be placed between it and the surface on to which it wants to “restick”. The non-stick interleaving layer can be sold under the brand Tyvek.

[0082] However, any barrier material can be used to separate the peeled material from the surface as it is peeled.

[0083] In one embodiment, a curve method can be employed to peel the sheet. A small starting section is peeled, and the non-stick interleaving layer of material is placed underneath the peeled part, butting up against the unpeeled section of the material. As there is continued peeling, the non-stick layer is moved up the tray. This can be done in either one smooth action, if by machine or many hands, or in incremental moves if fewer hands are there to do the actions.

[0084] Alternatively, a roll method can be used. In this method, a separate roller is used to transfer peeled material away as it is peeled. The roller can be gently lifted with the material in sections as the sheet is peeled. The non-stick interleaving material needs to be placed over the material as it is peeled and rolled onto the roll.

[0085] The large sheets of biopolymer thin film are preferably at least about 500, 610, 760, 1220 or 1524 cm in the shortest dimension. In an embodiment, the sheets are at least about 1 ,1.5, 2, 2.5, 3.5 or 4.2m in the longest dimension. Preferably, sheets are 1220mm x 4200mm. The sheets can be of any size and shape. The sheets size can be dictated by the tray size. A tray of about 2400 mm by 1200 mm can make a sheet that is about 2.3m by about 1.1 m once the edges of the sheet have been cut. Decals and stickers that are smaller can then be cut from the larger sheet.

[0086] To produce rolls for production, transport and storage sheets of the same width on the shortest side can be joined and added to a roll. This enables transport and storage of the material as well as optimal use in machinery and tools used for traditional PVC film.

[0087] For decals the thickness of the sheet matters considerably. Too thick and the material, being hydrophilic, will be liable to take on too much moisture and change too much over time. It also will not be as likely to form a bond with the surface to which is it applied that is capable of holding the weight of the material alone without a heavier adhesive, which introduces more petrochemicals in the double-sided adhesive film application. Additionally, a thicker sheet will be more difficult to use with an adhesive, as the ability for it to attract moisture will interrupt the adhesion. A thicker sheet will also be more challenging to cut using a hand or machine-driven blade.

[0088] When wet in the tray the mixture has a thickness of about 4mm to 5mm, but once set and dried this will decrease to about 1 mm. The order of shrinkage overall is about 75, 80 or 85%. In an embodiment, the biopolymer plastic film is at most about 0.25, 0.5 or 0.8mm in thickness for use as a decal. Slightly thicker decals can be tolerated in some circumstances.

[0089] For applications of the decal without a petrochemical applied adhesive or when the material is to be machined, thickness is a significant consideration. For best results in these kinds of applications, sheets should be less than 0.6mm or thinner. This allows for greater ease of adhesion with moisture alone, such as water, isopropyl alcohol or methylated spirits as well as more optimal results when machining the material.

[0090] The sheet material without any pigment added can be optically transparent with a slight yellow tone. This sheet is ideal for printing artistic designs of any printer- matched colour onto. If moulded evenly with smooth surfaces, it is smooth, shiny, clear and without any optical impurities. It mimics a clear piece of cellophane or vinyl in appearance. The additional of colourants and other textures in the production process alter the appearance, opacity, colour and texture. These coloured sheets may be more optimal for cutout lettering or shapes that do not require other printing, and thus may be reused or repositioned with greater ease. When printed, the movement of the material involved in repositioning can crack ink layers, impacting the reuse of the decal or sticker.

[0091] The addition of pigments and colourants to the liquid mixture enables the production of coloured sheet material with customisable properties such as colour, opacity and texture. As discussed above, a wide range of pigments can be incorporated to achieve specific visual and functional outcomes. The pigments can be selected from one or more of standardised inks, natural pigments, mineral pigments and finely ground metals. Standardised inks may be used to match colours commonly employed in traditional printing, ensuring compatibility with existing colour-matching systems. Alternatively, natural pigments, such as ochres or charcoal, can be used to introduce texture alongside colour, while maintaining the compostable nature of the material. These natural components also allow the finished product to carry greater cultural significance. For example, lettering cutouts could be composed of the same pigments used in accompanying artworks, creating a cohesive and meaningful design.

[0092] Metallic finishes can be achieved through the addition of finely ground metals, which provide a distinct and reflective appearance. Mineral pigments are another option, offering a wide array of colours while allowing for precise control over transparency, opacity, and lightfastness. These pigments ensure that the material retains its visual quality over time and under various lighting conditions.

[0093] The texture of the finished material can also be influenced by the choice of pigment or colourant. Fine powders or liquid colourants result in a smooth, even finish, while coarser powdered pigments introduce a matte or more textured surface. This versatility allows for a broad range of aesthetic and functional possibilities, tailoring the material to specific artistic or practical applications.

[0094] To achieve a uniform, shiny black material with consistent texture suitable as a replacement for thin-film PVC, specific methods and materials can be employed to add pigment to the liquid mixture. Due to the significant evaporation of water during the curing process, only a relatively small amount of pigment may be required to achieve an opaque thin film. For example, for a 14L liquid mixture, 14.06 grams of carbon black liquid mineral pigment can be combined with 1.49 grams of titanium white pigment. These pigments are exemplary Langridge Liquid Pigment Concentrates, consisting of artist pigments pre-dispersed in water.

[0095] The colour can be added, as discussed above, once the mixture has been well absorbed and is nearly ready for pouring. This timing minimises the pigment’s exposure to heat, reducing the risk of colour alteration due to thermal effects. The liquid pigment is incorporated into the mixture using a spatula or immersion mixer to ensure even distribution before pouring. This method step can result in a smooth, shiny sheet with a uniform black appearance.

[0096] In an alternative method, natural pigment in dried and finely ground powder form is used. To prepare the pigment additive, the material is sieved to achieve a fine particle size. For reference, fine sand particles are typically in the range of 0.125- 0.25 mm (125-250 microns). An appropriate sieve size for this range would be a mesh size of approximately 60-120 mesh. The sieved natural pigment is then added to the mixture in the same manner as any liquid pigment, using a spatula or immersion mixer to integrate the colour evenly.

[0097] The use of powdered natural pigment may affect the resulting material. The solid mass of the pigment particles may disrupt the smooth finish of the sheet, producing a matte or textured surface. This texture may also impact the material's ability to adhere to glass without adhesive, as the increased surface irregularity could interfere with the required contact for adhesion. While this method provides a visually distinct finish, it may less suitable for applications requiring a glossy, smooth surface.

[0098] The material is sensitive to hydrolysis. As a result, the material is impacted by atmospheric humidity and will soften and take on textures and impressions as well as shapes if it is exposed to humidity. Though it is relatively strong in tensile testing, as is seen in some of the preliminary tests where the sample shape was hand-cut, which introduced weaknesses to the material under pressure, the material is likely to tear if a perforation is present and put under tension.

[0099] Once the sheet has been prepared, an adhesive can optionally be applied. One method is to replicate the method commonly used with petrochemical decals, which is to apply a double-sided adhesive sheet (Jac Paper or similar) to the decal. In this method, the adhesive on one side of the double-sided adhesive sheet is exposed and affixed to the sheet. This is done before cutting the decal shape. The other adhesive side is used to affix the cut decals to the intended application surface. In all instances, the adhesive is applied carefully to form a seamless application free of air pockets or imperfections to the surface from introduced contaminants like dust, lint or other debris. Working spaces are clean and the sheet is wiped down prior to application to make sure there is no surface contaminants from transport.

[0100] In some embodiments, there is no applied adhesive film, and instead the film is applied through application with moisture or with an organic adhesive such as rice paste, wheat paste. Where moisture is to be the application method, water, isopropyl alcohol or methylated spirits can be used. The method for this application is to prepare the glass surface by thoroughly cleaning it. Using a manual pump sprayer or similar, covering both the application surface and the decal with a fine layer of moisture. Applying the decal and adjusting its position, then using a squeegee I decal applicator moving from centre to edges to remove any air pockets and as much moisture as possible by applying even pressure with the tool to the decal and moving over it from centre to edges. Using a lint-free cloth like a microfibre, wipe away excess moisture and clean the surrounding surface. It is advantageous to have the ability to adhere to glass surfaces without the need for adhesives, relying instead on a unique combination of material properties and application techniques.

[0101] It is thought that the gelatine plays a role in the ability of the thin film to adhere without adhesive. Gelatine has a unique protein-based structure that imparts elasticity, cohesive strength, and a tacky surface quality when moistened. Gelatine’s natural tackiness upon rehydration enables the material to bond tightly to the glass surface without synthetic adhesives. When moistened, it becomes flexible and the application of pressure with the squeegee / application tool stretches the material over the surface of the substrate. As the material dries onto the substrate, a tight bond is formed. The films ability to swell and rehydrate smoothly ensures a strong grip, creating a tight seal that conforms to the glass. These properties allow the material to adhere effectively to glass with a light mist of water. Agar, a polysaccharide, is thought to add stiffness and thermal stability but tends to form brittle, rigid films when used alone. Agar alone is thought to lack the adhesivelike swelling behaviour, but when combined with gelatine, the material is thought to achieves a unique balance of adhesion and conformability. The combination of gelatine and agar is thought to balance the characteristics, providing flexibility and elasticity alongside structural support and durability.

[0102] One of the most notable advantages of the thin film material is its flexibility, derived in embodiments from the gelatine content. This flexibility reduces brittleness and prevents cracking or tearing during curing, removal from mould, cutting, handling, application, or squeegee use. The material can conform seamlessly to the glass surface, maintaining its integrity even under mechanical stress. This is further enhanced by glycerine, which when present acts as a plasticiser to improve the material's pliability and usability during application.

[0103] As the material dries, it contracts slightly, further reinforcing the physical seal and locking the material onto the glass. This drying-driven fixation creates a durable bond that can be both strong and cohesive.

[0104] The sheet material can be machine-cut to specified artwork on a modular cutting machine or another vinyl cutting machine such as a plotter. The film can be cut before or after any adhesive is applied, dependant on the method for application. If using a double-sided adhesive film, cutting happens after adhesive is applied. If a non-applied adhesive like moisture or starch glue, the cutting is done first.

[0105] A digital cutting machine such as a plotter can be used to cut the biopolymeric thin film material into artistic designs. This machine is typically used to cut thin-film PVC or petrochemical non-PVC alternatives that are uniform in thickness and texture. For use in a plotter, there are additional mounting or adhesive application steps to be followed prior to cutting.

[0106] Mounting Specifications

[0107] The process begins by cleaning the side of the material cast onto glass with electrostatic rubber rollers to remove any dust or debris. Once clean, the mounting adhesive if required, can be applied. Not all adhesives are suitable for this material, especially during subsequent cutting and plotter use. Adhesives with PE liners or thin paper backings are unsuitable because of their lack of cushioning which causes the blade to pierce through the material instead of making clean cuts. The optimal adhesive, when present, features a softer, thicker paper backing, which acts like a sponge, allowing the blade to penetrate the material without damaging the backing.

[0108] Preferably, the adhesive is a clear lamination film that includes a double-sided solvent-free adhesive layer with an adhesive weight of 60g / m2and a white paper release paper that has a weight of 90g / m2. An example of this is Mountac HQ Clear permanent lamination film. In an embodiment, a commercial mounting table is utilised to ease the process of preparation and application of mount adhesive. A Lamidesk SuperSpeed CNC industrial application can be used to aid in application of the adhesive backing.

[0109] Printing Specifications

[0110] If the material is to be printed with details for the decal, this can take place before cutting. This allows for any print that is to occur on the edges to print a bleed that can be trimmed to achieve a clean print right to the edge of the cutout artwork.

[0111] The sheet material can be printed onto directly using a flat-bed printer or other direct-to-surface printing method, including silk-screening. The thin-film as decal approach can replace thin-film coatings used in place of paints or other aesthetic treatments applied architecturally.

[0112] The material is preferably printed using a Canon Arizona UV Large Format Flatbed Printer. This static bed printer throws ink onto the material without direct contact, ensuring the material remains stationary and accommodating its variability in thickness and elasticity. In embodiments, printing is completed with a clearance of 1 ,4mm maintained over the media to ensure proper ink application and avoid contact with the material.

[0113] Cutting Specifications

[0114] The material can be cut from the larger sheet into the decal / sticker shapes using a Graphtec FC9000 Series plotter. The material loaded as sheets. Achieving consistent cuts requires careful calibration of three critical factors: blade type, cutting speed, and applied pressure.

[0115] The cutting speed for this material can be slower than for standard PVC, at 4cm per second compared to the usual 15-20cm per second. This slower speed helps to prevent the blade from lifting corners or tearing the material. A heavy-duty plotter blade, such as those used for reflective or prismatic vinyl, is preferred. Preferred blades include the CB15UA-K30 and CB15U Graphtec blades. The blade angle and sharpness must allow it to slice cleanly through the material. Standard blades can be used but are less effective, as they require a speed reduction to 2cm per second, which is impractical for commercial workflows and results in less precise cuts and harder weeding.

[0116] Thinner sheets (<0.50mm) are ideal for faster, cleaner cuts, while thicker sheets (>0.70mm) are workable but require further blade adjustments. The maximum workable cutting length is approximately 5 meters, as most plotters and their associated software cannot handle longer lengths and offer functions to automatically cut rolls into sheets before cutting to shorten the feed and enable more stable cutting that prevents issues with skew on the feed that can result from directly cutting longer spans of material. Additionally, installers typically work with smaller sections for ease of handling during installation.

[0117] The designs can be loaded into Graphtec Studio software to be sent to the machine for cutting the material.

[0118] Weeding Specifications

[0119] Weeding involves removing excess material from a cut design, leaving only the intended graphics, text, or shapes. After cutting, the sheet remains attached to its backing paper and can be placed on a clean, flat surface. Using a tool such as a hook, tweezers, or a craft knife, the excess material can be carefully lifted and peeled away. Extra care can be taken to ensure that the cut pieces of the design remain adhered to the backing paper, especially for intricate designs or small text.

[0120] Internal elements, such as the centres of letters like "O," "A," or "B," can be removed using the weeding tool. Once all excess material is removed, transfer tape can be applied over the design. The transfer tape can be smoothed using a squeegee to ensure it adheres firmly and eliminates air bubbles. Finally, any backing paper can be carefully peeled away, leaving the design adhered to the transfer tape, ready for application.

[0121] Transfer tape specification

[0122] Medium-tack paper-backed transfer tape performs best for this method, as it provides sufficient rigidity and adhesion to hold the design securely. Low-tack paper and medium-tack plastic-backed tapes do not perform well, possibly due to the texture on the reverse side of the material. High-tack tapes may also be used. The preferred tape is Oratape MT72 Application Tape that uses natural rubber to achieve a medium-tack strength and that has a weight of 100g / m2 with the adhesive.

[0123] The rigidity of the transfer tape helps with reverse weeding. Thin paper or PE- backed transfer tapes fail because the plotter blade often cuts through the backing. Medium-tack paper tape with a thicker backing ensures the blade cuts cleanly without compromising the backing.

[0124] Reverse Weeding Method

[0125] Reverse weeding begins by applying transfer tape over the entire sheet before removing the backing paper to expose the adhesive. Excess material is then weeded while the design remains adhered to the transfer tape, which has a stronger adhesive than the backing paper. This method is approximately three times faster than standard weeding and produces clean, precise results. After weeding, the backing paper can be reapplied to the decals, preparing them for installation.

[0126] Artwork for cutting is usually supplied as a digital file and transferred to the cutting machine. In this laser cut method, the universal cutting tool is used with blade (type 6) and a thru-cut setting. Digital artwork designs are loaded to the machine and orientation checks are done to position the material. Simulations can be run to check alignment of cuts with the material. Slower cutting speeds are preferable to reduce drag on the material and endure cleaner cuts.

[0127] The blades on cutting machines must be sharp to ensure clean cuts on material. Procedures for machine cutting are followed depending on machine.

[0128] A plotter is best for material on rolls. The process for cutting on a modular cutting machine, which is the best method for sheets not on rolls, is as follows:

[0129] Artwork is setup for the machine and loaded onto it. Material is placed on the bed of the machine, aligned with placement corresponding to the artwork setup on machine. Material is secured with tape as additional backup to the machine’s surface vacuum that additionally holds material in place during operation. Blade is checked for shape and sharpness. Machine is initiated. Cutting begins. Machine moves blade to cutout artwork and then returns to default position. At this stage, app or transfer tape can be applied to aid application of decal. If applying transfer tape, this is smoothed over the sheet, and the negative form removed leaving only the artwork in place on the transfer tape, ready for application to a surface. Due to the through-cut method of this machine, an additional step is required to remove the adhesive backing paper from the weeded design, then replace this with a sheet of wax paper or non-adhesive transfer paper.

[0130] The material can be laser cut. However, due to the heat produced by laser cutting, and the sensitivity of the material to deform under high heat due to the changes in hydration in the material, it is preferable to use a blade-based cutting method.

[0131] Cutouts can be also made by hand with a utility knife. This method is suited to trimming decal applications to fit flush around existing features or fittings of an installation site, such as window edges, doorknobs or other permanent fixtures.

[0132] The material can have coatings applied such as UV coatings or other coating that improve its material properties in use.

[0133] The present thin adhesive film can be used in any location where previous thin films would find internal / indoor application. For example, the thin film could be used in exhibitions, retail spaces and or events where adhesive signage and artwork play a pivotal role in communication and aesthetics. The display provided by the thin film can be for promotional messaging, branding, for conveying information or the display can be just aesthetic e.g. an image.

[0134] Figures 1 and 2 show an example of the present decals used on a glass window of a commercial shop. Each of the decals has been cut to be shaped aesthetically or to resemble a product. One of the decals has the details of the product displayed so that customers walking past can read it. The decals or stickers are large pieces that are intended for display. In an embodiment, the stickers or decals once cut have a surface area of at least about 50, 100 or 250 cm2 or larger. The stickers / decals formed by the present thin film are typically not small items prepared individually, but are items cut from a larger sheet prepared by the method described. If the decal items are not cut out from a larger thin film piece, then the thickness and homogeneity of the individual items cannot be maintained, which can be aesthetically problematic. In relation to letters prepared using the thin film (for text display), letter of about 1 ,5mm line weight is about the smallest that could be commercially cut from the large piece of thin film although smaller items might be cuttable from the large thin film piece

[0135] Beyond commercial settings, the thin film could be used in an architectural context where they are applied to glass surfaces to provide privacy or safety markings. The film could also be used as a protective layer on building materials with smooth surfaces. In these contexts, materials like metal, acrylic or glass sometimes come packaged with a layer of plastic adhesive film that covers smooth faces of the material to protect them during transport and storage. These are typically removed once installation is complete.

[0136] In the realm of art, thin films have emerged as a compelling medium for expression. Artists can leverage the adhesive and malleable nature of the films to create impactful and visually engaging works. The transparency and versatility of thin films can allow for innovative applications, contributing to the dynamic interplay between materials and concepts. This artistic application further extends the boundaries of traditional mediums, showcasing the adaptability of thin films as a canvas for creative exploration in the realm of contemporary art.

[0137] The artwork decal is applied to a surface such as glass, metal, painted walls or other flat surface. Depending on the artwork, this may be done with a stencil cutout to assist with placement of each piece onto the surface. Additionally, refinement of application techniques to allow for artwork to be applied with the adhesive applied to surface and a transfer tape holding all the pieces in place together for easy application is under development.

[0138] The film can be removed in a similar way to regular decals, which is aided by a scraper to manually peel off the decal from a surface if adhesive has been used. In addition, and depending on the adhesive used, non-petrochemical decals may be removed more easily, by peeling easily without the use of a scraper. A fine spray of moisture can also soften the material and ease its removal.

[0139] One advantage is that where the material is used to apply biopolymeric decals to a non-porous smooth surface, such as glass, the biopolymeric decal can be removed without damage and repositioned or reapplied. In this embodiment, it can be reused.

[0140] One particular advantage of the present biopolymeric plastic over more widely used petrochemical decals is that this material can be recycled in a simple, nonindustrial process that involves boiling the plastic in water to bring it back to a liquid form, from which it can be re-set into new film or other forms. For this application as decals, there is often significant waste material in the counter-form - the negative of the artwork that is cut from. In this solution, the material can be recycled entirely. In an embodiment, there is no waste.

[0141] If the adhesive used is an applied adhesive film that is not compostable or dissolvable, this must be removed prior to this recycling process. This can be manually removed by peeling the adhesive off the material. It can also be achieved easily by soaking the adhered pieces in water over 8-12 hours. During this time, the non-petrochemical material will absorb water, swelling in the process and allowing the adhesive layer to separate with ease. At this point, the removed adhesive layer is disposed.

[0142] If a non-applied adhesive is used, such as moisture or a starch-based adhesive, the material can be recycled directly after removal from surface.

[0143] The present decal can therefore be recyclable. An additional innovation is the focus on re-making the material along with any waste from cutting, in decals. This application is well-suited to this as the installers who put the decals up are often called back to reinstall the next lot of artwork, and also deinstall the former. It is a perfect model for this external service delivery person to also collect the deinstalled decals and return them to be recycled. Online food packaging, which relies heavily on household or public waste which is more of a challenge to implement a recycling model to, this application as decals is well-fitted for the application of a closed-loop recycling model.

[0144] In a second aspect there is provided a first decal configured to be applied to a surface, wherein the decal or sticker is formed from a biopolymer thin film, wherein the first decal can be dissolved and then reformed into a second decal, the second decal being different to the first decal.

[0145] This type of plastic is more readily degraded by hydrolysis, which is also part of its strength, giving it the ability to be recycled in water readily. However, a consideration in its use is that it is not suitable for use in wet environments. It is not recommended for use outdoors. Due to the sensitivity to humidity, these types of decals must also be packaged, stored and transported in ways that protect them from humidity. They are preferably kept flat and free from creasing. Rolling is best for transport and storing sheets.

[0146] The best storage method for rolls of this material ensures protection from moisture and environmental fluctuations to maintain its quality and performance. Optionally, the sheets can be stored with a desiccant to avoid or at least reduce moisture damage. In an embodiment, therefore, each roll can be sealed in a moistureresistant packaging with a desiccant included inside to absorb any residual humidity that could detrimentally affect the material. The rolls should be stored upright in a sturdy, protective container, such as one made from durable cardboard, which serves as an adequate outer layer for this storage package.

[0147] The storage environment is preferably indoors, away from moisture, and maintained at stable conditions with minimal fluctuations in temperature and humidity. Exposure to extreme or varying environmental conditions can compromise the material’s integrity, affecting its performance during application. For optimal results, the material should be used within six months of production to ensure its properties remain intact and meet performance standards.

[0148] Over time (12+ months), the material can become brittle or change shape as a result of exposure to changes in ambient humidity and temperature. For this reason, this material is best made and used promptly, and is not recommended for permanent or long-term installations.

[0149] An embodiment of the invention is now described by way of example only. This embodiment is not limiting.

[0150] 380g of food grade E406 Agar (particles less than 0.3mm) derived from Gracilaria genus of red algae and 380g gelatine (particles less than 1 mm) were added to a vessel containing about 10L of water. The water, at a temperature of about 70-80 degrees C, was agitated to create a whirlpool prior to adding the agar and gelatine. The agar and gelatine materials were added gradually to avoid clumping and to ensure the best possible dissolution. A blender (fully submerged and held at an angle of about 45 degrees) was used to aid in dissolution. 380g glycerine was slowly added to the mixture during blending.

[0151] The water and agar / gelatine mixture was heated until boiling point was reached. The water was held at a rolling boil with heat set on induction hot plate to 130 degrees C. The temperature was then reduced, and the mixture was allowed to simmer to below boiling point (60 to about 80 degrees C). A lid was in place over the vessel while cooking to minimise evaporation. The mixture was left to simmer until it began to exhibit some optical translucency or transparency. After about 20 minutes the mixture was translucent to the human eye, and no visible granules appeared in the mixture under close inspection.

[0152] Before pouring, the mixture was evaluated for consistency and uniformity through small test samples. A small quantity (<1 ml) was dripped onto a test surface and allowed to cool. Once gelled, the sample was inspected for clarity, colour (indicative of the "wet" mix), and texture. Clarity was assessed by holding the sample against the light, while its resistance and consistency were tested by crushing it between the fingers. A properly mixed gel resists light pressure without breaking but crushes cleanly under firmer pressure. The mixture was further inspected visually for undissolved polymer, uneven pigment distribution (when added), bubbling, evidence of burning within the mixture or any other inconsistencies.

[0153] The consistency of the mixture was tested to ensure that there were no clumps and that it was freely pouring. The mixture was a bit thick for free pouring and required manual movement to flow from the vessel, so 500 mL of additional water was added and the mixture was re-blended. Upon retesting the pour, the mixture was thin and runny more than water and less than honey.

[0154] A piece of flat clean glass 2400mm x 1200mm was provided with a boundary layer (side wall). The mixture was poured onto the glass, steadily, with force behind it to spread the mixture across the glass and up to the boundary edges. The edges of the glass surface that were not covered in the first pour were then filled in with additional lower velocity pours. The mixture was then allowed to settle and selflevel. Following pouring, a heat gun was used to remove any bubbles in the exposed flat surface.

[0155] The mixture was allowed to cool on the glass into a gel. Once the material was set into a preliminary thin film, an incision was made along the immediate edges of the tray to separate the thin film from the boundary side wall. The cut was made to the depth of the tray base, through the full layer of gel. The film was then dried in a dryer or a dehydrator.

[0156] The dried film was removed from the glass by peeling. First, a border was cut around an inner sheet, and the outer borders were removed as waste. The remaining thin film was peeled from the glass on to a nonstick interleaving layer which was rolled onto a spindle during peeling. The sheet had a constant thickness of about 0.8mm.

[0157] Final evaluations were made include inspecting both sides of the cured sheet against the light to verify colour consistency and opacity. The cured sheet was evaluated for thickness using a digital micrometer, with checks for uniformity across the material. Colour swatches were used to assess colour matching and opacity, while surface properties such as smoothness, glossiness, or matte finish were visually inspected and matched to reference samples. The material’s strength was generally consistent with its thickness and was confirmed during handling and production stages.

[0158] An adhesive was applied to one side of the thin film. The adhesive was applied carefully to form a seamless application free of air pockets or imperfections to the surface from introduced contaminants like dust, lint or other debris. The thin film with adhesive was then machine-cut to specified artwork on a plotter.

[0159] The thin film material prepared was soluble, which provides the ability for it to be returned to a liquid and re-made into new material. In a test of this solubility, a piece of material 0.6mm thick, cut into a Test Strip 2cm x 15cm, was placed in boiling water (in a rolling boil, at least 100 degrees C). The Test Strip was at first agitated by the movement in the water as the vigorous boil creates movement in the liquid. After 15 minutes, pieces of the Test Strip had visibly broken apart. After 45 minutes, the Test Strip was in many smaller pieces. After 60 minutes, the Test Strip was not visible, and had integrated into the liquid. Once liquid was evaporated to remove excess water, the resultant liquid would set. When the set liquid was dried, new thin film material was formed.

[0160] The final composition should achieve specific properties, including uniform thickness, strength, flexibility, and the ability to be handled and removed from the mould without defects such as tearing, cracking, or bubbles. In addition to these functional requirements, the material must meet aesthetic goals such as precise colour, opacity, surface finish, patterning, and texture tailored to the intended application. For instance, an opaque, glossy black material designed for computercut lettering requires an ultra-fine or ink-based pigment that ensures a smooth, glossy finish after curing. Success in achieving these properties is consistently measured against benchmarks such as material thickness, tensile strength, colour consistency, and surface quality. Adhesion to glass or other non-porous surfaces without adhesive is achieved using the method detailed elsewhere in this document, involving carefully controlled steps to ensure reliable and repeatable outcomes.

[0161] Unless there is specific aesthetic objective for artistic effect, the material is benchmarked against PVC for both aesthetic and technical performance, ensuring it serves as a viable replacement. It is designed to be machined and produced using existing equipment and techniques, making it fully compatible with established workflows. The material has already been adopted in major cities across Australia, New Zealand, and New York, demonstrating its ability to perform at a high level both aesthetically and functionally. Its visual similarity to PVC "vinyls" in commercial applications validates its claimed properties and suitability for widespread use.

[0162] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0163] Where a document is incorporated by reference and there is conflict in the content, this document takes precedence.

[0164] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0165] Any promises made in the present description should be understood to relate to some embodiments of the invention and are not intended to be promises made about the invention as a whole. Where there are promises that are deemed to apply to all embodiments of the invention, the applicant / patentee reserves the right to later delete them from the description and does not rely on these promises for the acceptance or subsequent grant of a patent in any country.

Claims

CLAIMS1 . A method for forming a biopolymer thin sheet of film, the method comprising the steps of mixing, under heating, one or more biopolymers into water or a substantially aqueous liquid to form a mixture; optionally adding a plasticiser to the mixture; wherein the mixture is heated until the mixture becomes substantially optically translucent; causing a thin film of the mixture to set over a surface having a boundary to contain the mixture, the thin film of mixture having a first side in contact with the surface and a second side exposed to air; heating the second side to dissipate any air bubbles; allowing the thin film to set; once set, releasing the thin film from contact with the boundary; drying the thin film; and once dried, cutting the thin film to remove edge defects; and peeling the thin film from the surface to provide a thin film formed from a biopolymer.

2. The method of claim 1 , wherein the biopolymers comprises a polysaccharide in the form of agar and a polymer of amino acids in the form of gelatine.

3. The method of claim 1 or 2, wherein a glycerine plasticiser is added to the mixture.

4. The method of claim 3, wherein the mixture is poured into a tray and the surface is the bottom of the tray and the boundary is the wall of the tray.

5. The method of any one of the preceding claims, wherein the mixture is poured to a depth of about 4 to 5mm in thickness.

6. The method of any one of the preceding claims, wherein releasing the set thin film from contact with the boundary is undertaken by cutting the set thin film around the entire edge of the film.

7. The method of any one of the preceding claims, wherein the drying is undertaken in a desiccator.

8. The method of any one of the preceding claims, wherein once dried the dry film is less than 1 mm in thickness.

9. The method of any one of the preceding claims, further comprising the step of applying an adhesive to the thin film.

10. A method of preparing a decal or sticker comprising the step of cutting an artistic design from the thin prepared according to any one of the preceding claims.11 . The method of claim 9 comprising the step of applying the decal or sticker to a surface.

12. The method of claim 11 , comprising the step of removing the decal or sticker from the surface and dissolving it in water to form a mixture.

13. The method of claim 12, further comprising repeating the steps of any one of claims 1 to 9 to form a second thin film.

14. A biopolymer thin sheet of film prepared by the method according to any one of claims 1 to 9.

15. A decal or sticker configured to be applied to a surface, wherein the decal or sticker is cut form a sheet of biopolymer thin film.

16. The decal of claim 15, wherein the biopolymer thin film comprises a polysaccharide in the form of agar and a polymer of amino acids in the form of gelatine.

17. The decal of claim 16 further comprising glycerine.

18. A decal or sticker according to any one of claims 15 to 17 when applied to a surface.

19. A decal or sticker configured to be applied to a surface, wherein the decal or sticker is cut form a sheet of biopolymer thin film prepared according to any one of claims 1 to 9.

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