AU2017361120B2 - A compostable tableware - Google Patents

Abstract

A compostable tableware formed of a combination of rice husks or corn husks and a decomposable binder in the form of a gelatinised starch of particularly potato starch or wheat starch, a form of organic acid, a form of plasticizer and water.

Description

A COMPOSTABLE TABLEWARE

Field of the Invention [001]The present invention relates to a compostable tableware and in particular to a compostable tableware. The present invention is intended for food contact use. The materialis not limited to food contact application, but the nature of such an application tends to govern the type of raw materials that are permitted.

[002]The invention has been developed primarily for use in/With compostable tableware that can be used for one use situations such as take away food and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

[003]Background of the Invention [004]A problem with disposable tableware such as that used by fastfood outlets is that they are single use articles. Further after such single use the entire article is usually a total waste product that is disposed of in rubbish/garbage bins and sent to landfill. Therefore, the product has the problem of single use of good material and total landfill wastage after one use.

[005]Initially the disposable tableware was formed from plastic. However, many plastics take many decades of years to decompose and some do not decompose at all. Therefore, the landfill remains inert and rendered useless. If such products are not properly disposed of in landfill, this increase of non-decomposable product can result in strewn rubbish across the roadways and surrounding environment. This can cause direct damage to wildlife in the waterways and other environments and cause a general health issue. With no means of decomposition this environment can only be repaired by further action of collection of the strewn rubbish and to then transport it to landfill. This primary and secondary rubbish collection is costly, wasteful and of short term benefit in ensuring it is in landfill. That is it still is a non-decomposable product and still forms a long term concern in this waste format.

[006]This problem has been further exacerbated when fastfood outlets went to use polystyrenes due to its apparent benefit as a single use heat resistant. Polystyrene is an inexpensive and hard plastic and probably polyethylene or polypropylene is

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PCT/AU2017/051257 more common. The polystyrene is also in the form of foam packaging and insulation and therefore used to make drinking cups and food containers.

[007]When polystyrene is sent to the landfill, it is quickly covered. This process deprives the covered waste of water and oxygen, which would normally help it to break down. When polystyrene breaks down, it merely breaks down into ever smaller pieces of polystyrene. This is true for the majority of plastics used to make food packaging, including polyethylene and polypropylene. These small pieces of plastic (also known as micro-plastics) remain inert; and generally cannot be used by surrounding microorganisms. Micro-plastics pose a risk to wildlife, especially marinelife and birds. There is widespread documentation of harm caused by wildlife ingesting small pieces of plastics, mistaking it for food. Most of the disposable plastic food packaging we use today will take at least 500 years to decompose; the negative impact of this disposed packaging is continuous and ongoing. It is therefore imperative that alternate, wildlife-friendly food containers be developed.

[008]Also there are problems with polystyrene in use as it contains the toxic substances styrene and benzene, which are suspected carcinogens and neurotoxins that are hazardous to humans. Hot foods and liquids are believed to start a partial breakdown of the polystyrene, causing some toxins to be absorbed into our bloodstream and tissue. Further there can be a degradation of food. It is believed that food and particularly food which contains vitamin A are more prone to degradation in such polystyrene food containing articles.

[009] Polypropylene is the most common plastic after polyethylene. Many restaurants serve takeaway food in transparent polypropylene containers. Many restaurants will also provide customers with such boxes to take home their unfinished meals.

[0010] Single use petrochemical-based plastic food containers, including polystyrene and polypropylene containers, are a ubiquitous part of the food industry. The sheer volume of such containers produced is cause for concern due to their persistent environmental impact after disposal.

[0011 ] According to a study published by the journal S ciences Advances in 2017 regarding all the plastic ever produced on earth: Up until 2015, the global human population as a collective has produced 6.3 billion metric tonnes of plastic waste. Only

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9% was recycled. 12% was incinerated, and 79% ended up in landfill or the natural environment.

[0012] There has been a move away from polystyrene and polypropylene to use paper and cardboard products. This has the benefit of being more decomposable. It also has some benefit in being able to be made from recycled paper or cardboard. However, there is the problem in strength integrity and water permeability. Also, unless there is a complex fluting sandwich layering of paper sheets, there is not a sufficient temperature gradient that allows the user to hold a hot drink in such paper cup. A paper cup therefore is not merely a simple paper product but an engineered product of multilayers and a chemical product to stop water permeability.

[0013] Also, there are problems in the manufacturing processes. Ittakes a lot of energy to create paper products. This includes the heating, steaming and processing steps used in formation of paper products, while trying to avoid or limit further degradation of the length of the lignocellulosic fibrous material. Also in recycling there is a concern that the bleaching processes to remove print or the print itself on the paper or the chalk fillers are toxins, are difficult to process and are using at least as much energy to process as if processing from new wood supply.

[0014] Making paper products from virgin wood supply can mitigate these problems, but causes substantial problems when natural forests are logged to obtain this new wood. Logging of new wood from natural forests contributes to habitat destruction of animal species, and has a causal effect on climate change due to the loss of natural carbon sinks.

[0015] It can be seen that known tableware has the problems of:

a) source of material

b) value or cost of source material

c) difficulty of production

d) limitation of usage

e) structural integrity

f) toxicity

g) wastage

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h) environmental costand effect of wastage [0016] The present invention seeks to provide a compostable tableware, which will overcome or substantially ameliorate at least one or more of the deficiencies of the prior art; or to at least provide an alternative.

[0017] The present invention is currently intended for food contact use. However, the material is not limited to food contact applications. The nature of being intended for food contact use means that there is strict governance on the types of raw materials that are permitted. In a nutshell, for the material to be approved for food contact use, the choice of all components in the material must be recognised as generally safe, and/or be approved for food contact use. This varies according to country, but Australia mainly looks toward European Standards and American FDA standards. In the case of FDA standards, all ingredients within a food contact material must be GRAS (generally recognised as safe) or prior sanctioned. More information can be found by accessing the relevant government websites for the specific standards. It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

[0018] S ummary of the Invention [0019] According to a first aspect of the present invention, a compostable tableware is provided by a compostable tableware comprising t a shaped tableware;

t the body of the tableware formed substantially from decomposable material t the decomposable material is held together by a decomposable binder wherein the compostable tableware can be used as a tableware for supporting food. [0020] The compostable tableware can further comprise a decomposable food contactable surface on an upper side wherein the compostable tableware can hold food a nd not affect flavour of food.

[0021] Preferably the decomposable food contactable surface is formed by the decomposable material and can hold food and not affect flavour of food.

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PCT/AU2017/051257 [0022] However, in another form the compostable tableware has the decomposable food contactable surface formed by a decomposable layer over the decomposable material, which allows the user to hold the food with the decomposable layer preventing any effect on the flavour, taste or smell of the food.

[0023] Preferably the decomposable food contactable surface layer is biologically inert but structurally decomposable.

[0024] The compostable tableware can be one of:

i A bowl i A plate wherein the compostable tableware can be used as a food container.

[0025] However, in other forms the compostable tableware can be one of:

t A shaped handheld open top container t A shaped handheld closable open top container wherein the compostable tableware can be used as a single use food container.

[0026] Preferably the compostable tableware is formed from waste product [0027] In one form the waste product includes such waste primary products such as com husk.

[0028] In another form the compostable tableware is formed by the waste product which includes such waste processed products such as linen fibres.

[0029] Preferably the waste product includes a combination of such waste primary products and waste processed products.

[0030] The compostable tableware can have the binders holding decomposable material together including at least one of a range of gelatinised starches.

[0031] The compostable tableware can further comprise a compostable tableware formed from waste product including such products allowing variability of construction by mouldability and by mixtures of materials and by addition of surface coatings for food segregation and to avoid taste contamination.

[0032] The waste product can be held together by gelatinised starches that act as binders.

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PCT/AU2017/051257 [0033] It can be seen that the invention of a compostable tableware provides the benefit of usage of product which otherwise does not fulfil the benefit of compostability while not affecting food taste, smell and safety.

[0034] According to a second aspect of the present invention, a compostable tableware is provided by a compostable tableware formed from waste product including such products as com husk and held together by gelatinised starches that act as binders.

[0035] According to a third aspect of the present invention, a compostable tableware is provided by a waste product including such tableware, allowing variability of construction by mouldability and by mixtures of materials and by addition of surface coatings for food segregation and to avoid taste contamination.

[0036] In a particular form of the compostable tableware it is formed from waste product, including such waste products as corn husk combined with or without linen fibres and held together by gelatinised starches that act as binders; wherein the compostable tableware can be substantially assembled with improved usability and disposability including from any one or more of the following benefits:

i. improvements in structure ii. Improvements in structural integrity including better construction ill. Improvements in compostability iv. Improvements in usage of otherwise waste product

v. Improvements in minimizing loss of new material for single use takeaway food containers.

[0037] Other aspects of the invention are also disclosed.

[0038] Brief Description of the Drawings [0039] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

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Fig. 1 is a diagrammatic view of a compostable tableware in accordance with a preferred embodiment of the present invention that can be used for one use situations such as take away food;

Fig. 2 is a summary diagrammatic view of a method of forming of compostable tableware including the preprocessing steps and processing steps of forming compostable tableware that can be used for one use situations such as take away food in accordance with a preferred embodiment of the present invention;

Fig. 3 is a selection step of ingredients to form the material to form the compostable tableware that can be used for one use situations such as take away food in accordance with a preferred embodiment of the present invention;

Fig. 4 is a diagrammatic view of the different forms oftreatmentinthe production of a compostable tableware in accordance with the invention including chemical and physical treatments;

Fig. 5 is a diagrammatic view of a method of forming of compostable tableware including the preprocessing steps of forming compostable tableware that can be used for one use situations such as take away food in accordance with a preferred embodiment of the present invention;

Fig. 6 is a diagrammatic view of a method of forming of compostable tableware including the processing steps after preprocessing steps of forming compostable tableware that can be used for one use situations such as take away food in accordance with a preferred embodiment of the present invention;

Figs 7 to 10 are a more detailed process of manufacture which includes a combination of different processes of creating a compostable tableware of consistent material constituents or a layered patterned compostable tableware 257 which includes the industrial steps of:

I) Sheet extrusion ii) Die cutting;

ill) Rolling layers together; and iv) Ram press moulding or compression moulding.

Figs 11 and 12 are diagrammatic views of a more detailed process of manufacture includes a combination of different processes of creating a

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PCT/AU2017/051257 compostable tableware of a layered patterned compostable tableware which includes the industrial steps including in accordance with a preferred embodiment of the present invention including the steps of:

I) Sheet extrusion ii) Die cutting;

ill) Rolling different layers together; and iv) Ram press moulding or compression moulding.

Figs 13 to 17 are diagrammatic graphical views of the interrelationship of component elements including:

I) Starch to water ratio for effective starch ii) Effective starch amount and binding strength ill) Com husk size and ratio [0040] Description of the Preferred Embodiments [0041] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0042] Referring to the drawings and particularly Fig. 1, there is shown a compostable tableware 155 that can be used for one use situations such as take away food.

[0043] In one form a compostable tableware formed from waste product but more particularly formed from waste product including such products as com husk with or without linen fibres and held together by gelatinised starches that act as binders.

[0044] In still another form the invention includes a compostable tableware formed from waste product which allow variability of construction by mouldability and by mixtures of materials and by addition of surface coatings for food segregation and to avoid taste or smell contamination.

[0045] Still further there can be in one embodiment the basic formula of the compostable tableware which is formed from:

a) At least one type of natural fibre

b) A binder in the form of gelatinised starch

c) A form of organic acid

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d) A form of plasticizer

e) Water

f) Preservatives may be included [0046] In a particular preferred form there is provided a particular method of construction, including steps of construction that provides the stable base and allows variability of construction by mouldability.

[0047] It can be seen that the invention involves a number of components including:

a. selection of materials;

b. processes including pre-processing of material and post processing of combined material; and

c. overall approach to effect the synergistic result.

[0048] With regard to materials, in a preferred form of the invention with the intention of it being biodegradable and fully compostable in the right, care is ensured that all included raw materials are organic in nature (and therefore able to decompose) and pose no harm to the soil environment. Furthermore, some components are beneficial to plants. For example, potassium from potassium sorbate is an essential plant nutrient and is commonly found in commercial fertiliser.

[0049] Referring to Fig. 3, the raw materials that make up these embodiments can be divided into seven broad categories; as follows:

a) Natural Fibres

b) Water

c) Gelatinised Starch

d) Acids

e) Preservatives

f) Cross linking agents

g) Plasticisers [0050] Referring to Figs. 5 to 10 with regard to a method offorming compostable tableware, there is included in a preferred form of the invention the steps of:

a) Pre-procedure of preparation of waste material

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b) Procedure of selection of the material for the compostable tableware to be formed from a combination of:

i) At least one type of waste material in the form of a natural fibre ii) A binder in the form of gelatinised starch ill) A form of organic acid iv) A form of plasticizer

v) Water vi) Preservatives may be included

c) Procedure of creating mouldable material

d) Procedure of forming mouldable compostable tableware from mouldable material [0051] Method [0052] Referring to Figure 1 there is shown a method of forming of compostable tableware 110 including the steps of providing of waste consumable in step 111 and P re-procedure of preparation of the waste material in step 112.

[0053] Then in step 113 there is the combination of ingredients to form the material including the Procedure 120 of selection of the combination of ingredients for the compostable tableware as shown in Figure 2.

[0054] From this created material or putty formed from Procedure of creating mouldable material there is the Procedure of forming mouldable compostable tableware from the mouldable material in step 114 which is finally treated in step 115 to form a useable shaped compostable tableware wherein compostable tableware provides a stable base and allows variability of construction by mouldability [0055] The pre processing method 112 currently used is divided into two stages, dependent on the fibre:

The cleaned fibres are sheared down into the appropriate length.

i) For fibres such as cornhusk, this first shearing step is carried out against the grain.

ii) If the cotton/linen used is recycled fabric the direction of shearing should be in line or perpendicular with the weave.

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PCT/AU2017/051257 iii) If the cotton/linen use is in strands, then only the first step is required (such as for string) unless in the case of thick rope.

[0056] The shortened fibres are then further broken down into the appropriate width. This can use a wet shearing method through the use of an apparatus such as a domestic blender and food processor, whereby the fibres are sheered with the addition of water, results in a more even fibre size and less dust. This is especially the case with fibres that are rigid when dry, such as cornhusk. Another form is a dry shearing method has been successfully use in case of cotton/linen cloth. In the case of rope, the strands would need to be pulled apart.

[0057] As shown in a diagrammatic example in Fig. 5 the method for preft processing cornhusk 112 for use in making compostable tableware comprises the steps of:

1. Step 141 has the cornhusks removed from the corncob, or otherwise obtained as a bi product of other processes requiring corn. The cornhusks are picked and cleaned to remove any dirt and insects.

2. The cornhusks may either be fresh or dried. If the processed cornhusks will be stored indefinitely, the fresh husks are dehydrated after cleaning.

3. As per step 142 the cornhusks are cut into 7ft0mm long strips against the grain.

4. In step 143, the cornhusks are processed with water, sheared until the strips are separated into fibres.

5. In step 144 the cornhusk strips are boiled in vat of hot water for approx 30 mins until softened. This step also kills any bacteria present. A preservative may be added at this stage, so it has a chance to soak into the husks.

6. The processed cornhusks undergoes a process to remove water until about 70% water in weight remains.

7. In step 145, the pulp is pressed into blocks of equal weight and frozen.

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PCT/AU2017/051257 [0058] Referring to Figure 3 there is shown a method of construction of compostable tableware including the procedure 120 of the selection of the material for the compostable tableware to be formed from a combination of ingredients.

[0059] In the first step 121 there is at least one type of waste material in the form of a natural fibre which can be selected from a natural fibre. Preferably the natural fibre is one selected from Rice husks or Com Husks. However, the natural fibre can be one selected from Linen or Paper. This later selection is less preferable as they incur problems in sourcing and processing.

[0060] In the step 122 of the selection of the gelatinised starch, this is selected from one or more of the high amylose starches of:

a) potato starch,

b) wheat starch

c) tapioca starch.

[0061] More preferably is the use of potato starch due to its greater versatility.

[0062] In the step 123 of the selection of the organic acid is selected from one or more of:

a) Citric acid

b) vinegar [0063] In the step 124 of the selection of the plasticizer is selected from one or more of:

a) Glycerol,

b) citric acid and

c) potassium sorbate [0064] In Step 125 there is water added sometimes upto 20%. Preservatives may also be included [0065] It should be noted that the importance of selection of the materials and matching has been explained in detail above by experiments and result in at leastthe listed examples below.

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PCT/AU2017/051257 [0066] The diagrammatic example ofthe preprocessing is shown in Fig. 5 has the method for preprocessing 112 and combining the ingredients to produce compostable tableware comprising the steps of:

1. Pre prepared cornhusk fibres are measured out.

2. The cornhusk is mixed thoroughly with the remaining ingredients. This may include a form of preservative.

3. The mixture is heated over a very low heat with continuous agitation until the starch is fully gelatinised.

[0067] A diagrammatic example ofthe processing is shown in Fig. 6 in which the method for processing the ingredients 113 to produce shaped compostable tableware 255 comprises the steps of:

1. Mixing the constituents in step 146 and applying heat in step 147 to create a compostable tableware putty 148

2. The compostable tableware putty 148 is manipulated into the required form by process 114 either by hand or via mechanical means. A mould may be used. At this stage, a form of compression moulding is suggested for production. As an example, in step 149 the putty is rolled in step 149 and then placed over mould in step 150 and made in step 151 to comply with the shaping ofthe mould.

3. The formed Compostable tableware putty 152 becomes compostable tableware 155 when in step 153 it is baked in an oven at 105eC < 120e until 90% jp5% dry.

4. The baked compostable tableware 155 is packaged and then stored in a cool, dry place until it is required.

5. At the end of its life, compostable tableware 155 can be fully composted.

[0068] Manufacture [0069] However, Referring to Figs 7 to 10, and 11 to 12 a more detailed process of manufacture includes a combination of different processes of creating a

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PCT/AU2017/051257 compostable tableware 255 of consistent material constituents ora layered patterned compostable tableware 257. Both include the industrial steps including:

a) Extrusion 301,

b) die-cutting 302, 303

c) rolling and combining 304, 305

d) compression moulding, 306, 307 and 308, and

e) heating 309 and

f) cooling 310.

[0070] In Figs 7 to 10 there is:

a) STAGE ONE: EXTRUSION

Extrusion is the process of forcing a material 251 through a suitably shaped hole by a ram 261 to create a long, consistent profile 252 with a specified cross-section. Cornhusk compostable tableware component and other Compostable tableware component would be fed separately into an extrusion machine to create a sheet. This is fed along a conveyor 262.

b) STAGE TWO: DIE CUTTING

Die cutting 263 is a computer controlled process where thin sheet material is cut into shape using steel knives, following a preset guide. The Compostable tableware component sheets 253 would be cut into disks, and other Corn husk compostable tableware component sheets would be cut into pattern pieces

c) STAGE THREE: ROLLING

The die cut pieces 253 which would be arranged and stacked in three layers 254 to form the pattern which is compressed when it passes through the pinch rollers 264, 265 over the conveyor line 266. The stack is passed through rollers 264, 265 and fused into one body 254 to prevent them from coming apart.

d) STAGE FOUR: RAM PRESS MOULDING

The fused layers 254 of Compostable tableware component are put into a ram press to be moulded.

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PCT/AU2017/051257 [0071] Referring to Fig. 9, the most appropriate method of manufacturing plain compostable tableware is Ram Press Moulding, which is a type of compression moulding. This method is used to manufacture multiple replica ceramic parts with permanent moulds. The process is suitable for all clay, and possibly clay-like materials. It is commonly used to produce crockery so it would be a fitting process for compostable tableware, especially given the material Compostable tableware components similarities to ceramic clay.

[0072] During the process of ram press moulding, also known as ramming or ram pressing, clay is forced into sheet geometries using permanent moulds. As the upper and lower Compostable tableware ingredients are brought together, a pressure between 100-400 psi is provided by hydraulic ram 274 and metal frame 275 to evenly distributed the pressure across the convex mould 276, and substantially complementary convex mould 276 held therein, to produce even and uniform parts 255.

[0073] During this process, the pressure of the two mould halves 276, 277 converging automatically cuts the flash 256 (excess material) from the part 255. The moulds are often made from plaster, which have a limited life span. The benefit of plaster is that it absorbs moisture away from the material during the moulding process, thereby accelerating the hardening process. The plaster moulds 276, 277 are secured into the metal frame 275 on the press and can be replaced whenever necessary.

[0074] There are many unknowns that surround the simple method of multi-shot injection moulding. As such, an alternate method of manufacturing is presented here. A more feasible way of manufacturing patterned compostable tableware is to use a combination of multiple processes. Many simply made_mass manufactured goods utilise multiple processes so the any perception of 'overly complex manufacturing, is really a nonissue. The method is adapted from the manual Three Layer System used to hand make patterned product.

[0075] e) COMPLETING THE COMPOSTABLE TABLEWARE [0076] After forming the vessels are not yet dry. As such they would need be placed onto racks and into an industrial sized oven 281 to dry. The temperature would

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PCT/AU2017/051257 preferably not exceed 120eC and preferably be 105eC. The dried Compostable tableware 255 would then be cooled, stacked and packaged for distribution.

[0077] With reference to Figs. 11 and 12, in a particular form of the invention in which there is the industrial steps including:

a) Extrusion 301,

b) die-cutting 302, 303

c) rolling and combining 304, 305

d) compression moulding, 306, 307 and 308, and

e) heating 309 and

f) cooling 310.

[0078] In this form at step 302 and 303 there are layers of different material or different colouring or different constituents. In this way there can be die cutting of different shapes in different layers in step 302 and overlay in step 303 of the different layers. Then by rolling and combining the multiple layers through the pinch rollers in step 305 there is a patterned combined and compressed material that can proceed through the compression moulding steps 306, 307 and 308 steps. This patterned moulded compostable tableware 257 can proceed through the heating 309 and cooling steps 310 to provide a tableware that is self-supporting patterned and fully compostable.

[0079] Material - Natural Fibres [0080] The intended application of the material is important to consider because otherwise an unsuitable fibre could be used.

[0081] This varies according to country, but Australia mostly looks toward European Standards and American FDA standards because few Australian-specific regulations have been developed. However, a code is present in the manual of Australian Standards that control the migration of chemicals from packaging into food. In the case of FDA standards, all ingredients within a food contact material must be G RAS (generally recognised as safe) or prior sanctioned. In the case of natural fibres, some general points to considerate:

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a) If it contains pesticides, it should be within a limit that is safe for humans.

b) The fibres should not contain any heavy metals or toxins.

c) Any bleaches and dyes that may leach out of priorjreated fibres must be within a safe limit and not prove harmful to humans when ingested in small amounts.

[0082] The primary function of natural fibres is to reinforce the material Invention while adding bulk. The fibres are held together by a binder, operating much like the role of fibreglass in resin by proving. The crossing strands of fibres provide non£ reactive (not dependant on chemical reaction) cross Jjnks.

[0083] The secondary function of the natural fibres is to give the material of the compostable tableware of the invention a unique aesthetic. It is a positive side effect of the natural fibres that increases the visual interest of the compostable tableware.

[0084] The choice of fibre influences the appearance of the material the most, since the starch binder is white and turns translucent upon gelatinisation. There is at least as much fibre by volume to the starch. In essence the colour of the fibre is primarily the colour of the resulting compostable tableware. However natural food safe product colouring can be used.

[0085] Different types of fibres in the material can result in a different material colour. In the case that different fibres are mixed, interesting patterns and colour combinations can be formed.

a) Cornhusk provides a green/yellow colour

b) Bleached cotton/linen provides a white colour

c) Unbleached hemp provides a light brown colour

d) Coloured cotton/linen can provide any number of colour but the colouring agents must be safe.

e) Natural dyes such as beetroot juice and approved food colourings may be added.

[0086] The type of natural fibre chosen is important, and could impact the performance of the material Invention. Natural fibres include but are not limited to:

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PCT/AU2017/051257 cornhusk, cotton and linen; however, these three fibres have demonstrated to be successful as reinforcement in the material. Examples of other fibres include hemp, wool, rice husk and corn silk.

[0087] The natural fibre chosen should preferably be porous (such as cornhusk, cotton and linen) because it would enhance its ability to reinforce the material. A porous fibre works better because gelatinised starch can lodge itself into the gaps during the wet material preparation process, therefore when the material is dry the fibres are harder to pull out; the resulting material is stronger.

[0088] The fibres used need to be pre processed in advance to an appropriate size by mechanical means such as shearing. The fibres are currently specified to be <20mm long and <5mm wide. The specific size which is currently used is approximately 10mm long and 1mm wide. However, depending on the application of the material, the fibres could be much longer (for example >30mm); there is no specific limit as long as the fibres are adequately spread out and able to be held by the binder material.

[0089] The amount of natural fibre used in the material Invention is currently between 5% and 6% by weight. However, any amount between 2% to 8% could work.

[0090] The amount of natural fibre used in the material is currently between 5% and 6% by weight. At this ratio, there is approximately a 1:1 ratio of fibre to gelatinised starch. At this ratio the gelatinised starch is able to wrap each fibre.

[0091] There is little advantage in adding less than 2% by weight of natural fibre. Any less than 2% by weight, there would not be enough fibres to offer structural reinforcement. 2% is possibly the lowest limit unless the fibres are only added as a colorant for visual interest.

[0092] However, the amount of fibres can be increased to saturation point, which is defined as a maximum amount of fibres that can be contained in the material on the condition that the gelatinised starch is able to fully envelope each fibre. This saturation point is estimated to be up to 8% by weight, assuming 27% of dry starch by weight in the material. If more starch is added, then more fibres can be accommodated, but that would also affect the amount of other raw materials added.

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PCT/AU2017/051257 [0093] Water [0094] There are two main functions to water. Both are applicable to when the material is prepared in its putty form: The first function of water is to gelatinise the starch component of the material.

[0095] Water is an essential component in the starch gelatinisation process. When heat is added to a mixture of starch and water, the starch granules swell as water enters the granular structure. Eventually the granules swell so much that they lose mechanical strength and 'burst,. The starch helices unwind, releasing molecular amylose and amylopectin. Fully gelatinised starch transforms from opaque to translucent.

[0096] The second function of water is to act as a solvent.

[0097] Some components of the material need to be dissolved in water in order to become activated and well incorporated. This includes certain organic acids in its crystalline salt form such as citric acid, and preservatives in solid form such as potassium sorbate.

[0098] Citric acid must be dissolved in water in orderfor it to be useful in the material, no matter what function, because sufficient water is required fora chemical reaction to occur. This includes the use of citric acid to lowerthe pH of the material, to perform acid hydrolysis, and as a cross linker.

[0099] The preservative potassium sorbate is inactive in its salt form. Once it is dissolved in water it turns into sorbic acid, its active form.

[00100] The water in the material Invention can come from sources otherthan what is directly added. Some raw materials contain embedded water, referring to the amount of residue moisture left in the material.

[00101] For reference, the water embedded in other materials will be named as 'carryover moisture,. Carryover moisture may be found in liquids such as vinegar, which is often sold diluted in water. Carryover moisture may be found in the natural fibres being used. The natural fibres could be wet due to being cleaned in water, or water could be used during the shearing process; in the case of cornhusk both cases apply. The exception is if the wet fibres are dehydrated before use.

[00102] Other ingredients may contain some carry-over moisture, but this is rather

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PCT/AU2017/051257 insignificant For instance, starch powders are generally dried to approximately 12% moisture, but this level can be affected by the relative humidity of the storage conditions and how long the starch has been exposed to air. The amount of moisture can be as much as about 20%. Moisture should be controlled to minimise conditions favourable to aiding microbial growth. The amount of water in the material Invention directly affects its physical properties.

[00103] The total amount of water used in the material currently ranges between 59% §3% by total weight. A range between 50% and 70% is acceptable. This amount of water is inclusive of the potential carryover moisture contained within all the other raw ingredients.

[00104] The exact ratio of water required in the material depends on the ratio of other ingredients contained within the material Invention, and their individual moisture levels.

[00105] The dryness of the natural fibres can be affected by seasonal variance, and different fibres exhibit a different coefficient of water absorption potential; both of which need to be taken into account. For example if the natural fibre is dry and particularly absorbent then more water would need to be added to the material as less free water would be available to the starch forgelatinisation. The current amount of water recommended refers to corn husk with around 30% moisture content.

[00106] The same is true for starches that are particularly dry; more water would be necessary to fully gelatinise the starch. The amount of water in starch can be affected by the relative humidity of the storage conditions. The current amount of water recommended is for starch at around 20% moisture contentlf not enough water is added, a number of issues arise. Water below 50% by weight is not recommended.

[00107] Water allows for the ingredients to freely move around, especially when the starch is gelatinised because it becomes thick and viscous. If there is not enough water, it would too hard to stir and combine all the ingredients together evenly.

[00108] Since heat is required forgelatinisation, it is inevitable thatsome of the water will evaporate from the material during the process. If there is not enough water, the starch may not fully gelatinise as there won't be enough water for the starch to absorb until it bursts. Un-gelatinised starch returns to its opaque powder form when dry. A clump of un-gelatinised starch will form a weak point in the material, where the material

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PCT/AU2017/051257 will crumble and break apart.

[00109] If there is not enough water, the ingredients that rely on being dissolved to be useful wont be activated. There needs to be enough water added to the material when it is initially being prepared to both dissolve certain ingredients and fully gelatinise the starch.

[00110] If too much water is added, then it will impact the curing and final form of the material Invention. No more than 70% weight of water is recommended.

[00111] Too much water will mean excessive drying and curing time. The cured material relies on water being expelled from the starch. The curing temperature is preferably limited to about 105eC to 120eC otherwise the material may form air pockets and warp. This temperature range is given due to difference of heating from conventional ovens to fan-forced ovens due to evenness of heat dissipation. The curing temperature can be lower than 105eC to 120eC but the material would take longer to dry and cure, therefore no more water than functionally required should be added.

[00112] More water in the material means more scope for the material to shrink and contract when the water is evaporated off during the drying and curing process. Whenever a material shrinks and contracts it is prone to warping. If the material warp cannot be controlled or is excessive, it becomes a quality control issue. It is best to add the least water possible.

[00113] The material is cured after it has been formed, whereby water is expelled so thatgelatinised starch hardens. An amount of waterwill still remain in the material. It will never be 'bone dry_. The recommended moisture level for the material once cured is between 4% and 10%, and should be kept within this range.

[00114] It is not necessary to dry the material to 100% dryness during the curing process because it will eventually absorb some moisture from its surrounds. Furthermore, a cured material that is too dry is more brittle and less flexible than a material where a greater amount of moisture is left. A cured material with too much moisture may be prone to microbial grown, owing the large amount of organic matter it is comprised of.

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PCT/AU2017/051257 [00115] Gelatinised Starch [00116] A function of gelatinised starch is to act as the binder that holds the natural fibres in the material Invention together.

[00117] The starch used is added to the material in its un gelatinised powder form and undergoes a gelatinisation process when liquid containing water is added.

[00118] When starch is gelatinised, molecular amylose and amylopectin is released. Amylose and amylopectin are a type of starch polymer and may be referred to as a type of biological plastic (also known as bioplastic). When starch is stirred during gelatinisation, these polymers begin to entangle and snare, creating a structure that forms the main support structure of the material.

[00119] When gelatinised starch retrogrades, it loses water and hardens. This gives the material of the compostable tableware ofthe invention its rigidity.

[00120] When gelatinised starch dries, it begins to retrograde. This most common example of this process is when bread goes stale; the starch component loses water and becomes hard. The act ofthe starch expelling water as it retrogrades is called syneresis. This process is essential so that the material is hardened; it is the hardening that gives the material its strength. For the material, this process of hardening will be referred to as 'curing,. A fully cured material is dry and no longer floppy, but the level rigidity is dependent on other factors.

[00121] Certain starches are preferred overothers, especially high gmylose starch. Potato starch is currently used.

[00122] There is evidence that starch higher in amylose creates a stronger bio plastic than amylopectin, and the cause may be due to the unique structures of both polymers. Amylopectin is shortand branched while amylose is long and unbranched. It was found that amylopectin glycerol films were more brittle and less flexible than amylose pectin films due to the distinct structure of the two starch polymers. The use of starch that is higher in amylose than amylopectin is therefore preferable.

[00123] All starches contain both amylose and amylopectin. Of natural (non]] chemically modified) starches, potato starch is relatively high in amylose. Experiments have shown that material (Invention) made using potato starch exhibit less fragility than those made with other starches such as com starch. Invention is

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PCT/AU2017/051257 therefore currently made using potato starch, but other high amylose starches such as wheat and tapioca could be used. There also exists on the market a number of starches chemically engineered to contain a very high percentage of amylose, up to approximately 80%.

[00124] Otherwise, natural starch can be engineered to contain more available amylose starch through means of acid hydrolysis, where amylopectin starch polymers are broken down more readily than amylose starch.

[00125] A function of gelatinised starch is to act as the binder that holds the natural fibres in the material Invention together.

[00126] Gelatinised starch is able to hold the natural fires together because it is thick and viscous; the natural fibres become trapped in the mixture. In the case of porous natural fibres, there is an increase of surface area for the starch to become entangled in. Since the gelatinised starch used in the material undergoes acid ft hydrolysis, it becomes sticky and the natural fibres become adhered to the starch.

[00127] The material Invention is currently cured ata temperature of <105eC.

[00128] An oven temperature of 105eC is supported as an optimal curing temperature in literature pertaining the making of starch films. This is also the temperature at which reactive cross|nks are achieved. (Such as through the addition of citric acid whereby citrate fttarch cross ftnks are formed) [00129] In independent experiments, 105eC in a fan-forced oven was found to be the most suitable temperature for drying and curing the material of the compostable tableware of the invention.

[00130] A summary of the test procedures follow:

a) Airftlrying was initially tested as an energy efficient way of drying the material, but this method took nearly a week and the lack of high heat meant that the potential for microbial growth was real. This means thatthis method would be unsuitable for food ftontactftnaterials.

b) A rudimentary solar oven built from cardboard and foil was tested. The temperature of the oven was monitored though an Arduino micro ftomputer fitted with a DH22 T emperature and Humidity Sensor. The interior of the oven reached a maximum of 58.3eC and the relative humidity recorded at the time

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PCT/AU2017/051257 was 7.8%. This represented the optimal conditions when the weather was sunny with an external air temperature of 22eC. The average temperature of the oven was only about 25eC, so the samples took two days to dry in the oven. A commercial solar oven would have been much more efficient, but if this material is to be made in commercial quantities, it would still not be as efficient as a fan-forced oven.

c) A conventional oven initially set to 50eC then turned up to 80eC meant excessive drying and curing time of approximately 6 hours.

d) In a conventional oven it was found that higher temperatures such as 120eC caused air pockets to form, which warped the material.

e) The temperature of 105eC is the most suitable temperature for drying and curing Invention. It is the hottest temperature the material can bear without excess deformation.

f) The amount starch powder used in the material Invention is in the range of 27% and 28% by overall weight This amount of starch yields enough gelatinised starch to fully encase the natural fibres of the material together, as well as act as the support structure of the material once dry. The properties of gelatinised starch are affected by water content and the presence of other materials.

g) The amount of water added to the starch plays a crucial role in how well the starch is gelatinised, and how thick it is.

h) The amount of acid added to the gelatinised starch to induce starch acid hydrolysis also affects its structure.

i) The amount of cross linking agents and plasticisers added to the gelatinised starch also affects its structure.

[00131] Acids [00132] The primary function of acid is to lower the pH of the material Invention, but a low pH is useful in a number of ways:

[00133] 1. A low pH induces acid hydrolysis of starch [00134] Acid hydrolysis starch refers to the act of acid breaking down and degrading

WO 2018/090087

PCT/AU2017/051257 starch polymers. Natural starch can be engineered to contain more available amylose starch by means of acid hydrolysis. Amylose is generally preferred over amylopectin when it comes to creating a stronger starch structure. Amylopectin undergoes acid hydrolysis more readily than amylose.

[00135] The amount of acid used determines the rate and extent of acid hydrolysis. Studies have shown that after the acid is added to the starch, the pH mustnotbe higher than pH4.0 otherwise acid hydrolysis may not occur.

[00136] Independent experiments with the material has shown that the more acid added, the greater the extent of hydrolysed starch. When the starch is hydrolysed, it becomes sticky. An overly sticky material is hard to work with, but a slight amount of stickiness allows the material putty to be reformed a greater number of times before it begins to set and cure. Separate tests using vinegar and citric acid were performed.

[00137] The findings are summarised below:

c Material samples containing at least 50% vinegar by weight were overly sticky before curing and therefore hard to work with; the material would stick to anything porous;

c Material samples containing approximately 25% vinegar by weight were just bearable to work with;

c Material samples containing below 10% vinegar became less sticky as less vinegar was added;

c Material samples containing more citric acid were sticker than those containing less;

c Material samples containing 5% citric acid or more by overall weight were overly sticky;

c Material samples containing 0.05% < 0.33% citric acid by overall weight were sticky, but workable; and c Material samples containing a maximum of 0.03% citric acid by overall weight were not sticky.

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PCT/AU2017/051257 [00138] Table 1

How the concentration of citric acid affects the stick!ness of the material putty samples
PH 2.0 @ 5.0% citric	Very sticky	Very sticky	Sticky
Acid
PH 2.0 @ 0.33% citric acid	Sticky	Sticky	Sticky
PH 2.5. @ 0.13% citric acid	Sticky	Sticky	Slightly sticky
PH 3.0 @ 0,05% citric acid			Not sticky
PH 3.5 @ 0.03% citric acid	Not sticky	Not sticky	(not tested)
PH 4.0 @ 0.01% citric acid	Not sticky at all	Not sticky at all	(not tested)

[00139] A low pH slows down or inhibits microbial growth in organic matter [00140] A pH level of maximum 5.5 but preferably lower, is well documented in literature pertaining food safety to reduce and even inhibit the ability of microbes to grow.

[00141] Microbes can only survive within a certain pH and if this is disrupted, the microbe is compromised. The table below charts the pH lower limits or growth range 10 for microbial growth. It is based on a chart contained in the book Handbook of Food

Preservation. Some of the listed microbes are responsible for causing many common food |)orne illnesses.

[00142] The efficacy of acids depend on their ability to equilibrate across the microbial cell membrane and in doing so, interfering with the pH gradient that is 15 normally maintained inside the cytoplasm of the cell and the food matrix surrounding it. Food is essentially a type of organic matter, so the following chart can be referenced for the material being developed. It does not mean it can be completely relied upon, but it provides a general guideline nonetheless.

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PCT/AU2017/051257 [00143] Table 2

Thelowest PH limit for growth range/minimal growth of common food microbes

Moulds (in general) Yeasts (ingeneral) Bacteria (in general) Acetobacteri um sped es Bacillus acidocaldarius

Clotridiumbotulinium Enteroccus faecal is Escherichia coli Listeria monocytogenes Salmonella species Staphylococcus aureus Yersinia enterocolitica

1.5-11	/////////////////-///>
1.5-8.5
4-9	-
2.8-4.3	4.0-6.0
2.0-5.0	5.9-6.1
5.3
4.5	-
4.4-9.1	7.2-7.4
4.4-8.7	7.5-8.2
4.3
3.8	///////////////////////-////
4.0
4.4	-

[00144] The pH level currently set for Invention ranges between pH2.0 and pH3.0, 5 which is sufficient against most bacteria.

[00145] The lowering of pH alone is not enough to offer broad spectrum protection against all microbes. For example moulds and yeasts can survive in extreme pH levels as low as pH 1.5. Therefore a low pH level is best paired with an additional preservative.

[00146] A low pH assists in activating the full potential of preservatives. Certain acids, especially organic acids, also work symbiotically with preservatives to increase the efficacy of antimicrobial activity.

[00147] The activity of potassium sorbate/sorbic acid is directly affected by the acidity of the material in which it is added. At pH 3.0 or lower the maximum potential 15 of potassium sorbate/sorbic acid is activated. The following table shows the effect of different pH levels on the activity levels of sorbic acid and potassium sorbate.

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PCT/AU2017/051257 [00148] Table3

T he effect of different PH levels on the activity levels of sorbic acid/potassium sorbate
PH of th® mixture

[00149] Citric acid itself is considered antimicrobial, but its effectiveness is most pronounced when it is used in tandem with another preservative whereby a synergetic effect is observed. The activity of potassium sorbate/sorbic acid is further enhanced by the addition of organic acids such as vinegar and citric acid.

[00150] A mix of >0.15% citric acid and 0.1 g.2% potassium sorbate is being considered for use in the material.

[00151] 0.15% citric acid results in a material with a pH level of 2.0. Potassium sorbate in its activated form becomes sorbic acid. The amount added to the material is unlikely to push the pH any lower, but if it does, it means that the material would likely be even more effect against bacteria based on pH alone.

[00152] Citric acid is preferable over other organic acids such as acetic acid (vinegar). Citric acid is more functionally versatile than acetic acid and when used as part of a food contact material, is less likely to taint food.

[00153] This ISO (international standards organisation) definition of taint is a taste or odour foreign to the product. In terms of food contact materials, any food contact article made from the material must not impart any foreign taste or odour to the food it is holding.

[00154] Vinegar is able to induce acid hydrolysis and as an organic acid, is antimicrobial to some extent. When vinegar is compared side |>y gide with citric acid, it is more effective against certain bacteria.

WO 2018/090087

PCT/AU2017/051257 [00155] However, vinegar has a noticeable odour that may be off putting even in small amounts, especially when emitted from a food contact article. This means that it is highly likely to impart odour taint to food, which is unacceptable.

[00156] Citric acid is able to perform both aforementioned functions of acetic acid without any odorous side effects. This means it is very unlikely to impart odour taint to food. Furthermore, the citrate component of citric acid means it is able to form cross Jjnks in starch, further enhancing the strength of the structure.

[00157] The issue of taste taint is another matter, and depends on the concentration of acid used. A taste test was performed on a number of Invention test 10 formulations containing varying amounts of citric acid. The results represent what was tasted directly from the material, not the taste taint effect on food. It is likely that if any taste taint is to occur, it would only be a fraction of what is tasted when the material is directly placed in the mouth and chewed.

[00158] The result of the experiment is summarised below:

[00159] Table 4

How different citric acid concentrations affect the direct taste of the material when chewed
	SSOssls®
		(Control) Extreme sourness that tasted salty.
ΐ Citric acid crystals, one pinch	100%	After rinsi ng mouth out, there was sweetness and then a strong metal I i c aftertaste.
i 1.5 mm thick dry wafer i sample		Distinct sourness that lingered, followed by sweetness and a metallic aftertaste the citric acid.
ΐ 1.5 mm thick dry wafer ΐ sample	0.33%	V ery mi I d sourness that remai ned for only a second, followed by sweetness and a metallic aftertaste the citric acid.
i 1.5 mm thick dry wafer	0.13%	No sourness detected, only a slight
i sample	metallic aftertaste
ΐ 1.5 mm thick dry wafer ΐ sample ί 1.5 mm thick dry wafer sample	0.05% 0.03%	No taste detected No taste detected

[00160] It was found that the less citric acid present in the material, the less taste there was in the material. An amount of approximately 0.15% citric acid was previously mentioned to be an optimal amount to use as an antimicrobial in tandem

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PCT/AU2017/051257 with potassium sorbate. At this concentration, no sour taste was detected from the material. However, there was a very slight sweet, citrus flavour. At even lower concentrations of citric acid, this was barely detectable. This means that it is very unlikely that there will be any taste or odour taint imparted from citric acid to food when used in the amounts specified. Nonetheless the material will be subject to approval by the relevant authorities and it may be the case that an external barrier coating may be required to prevent sensory taint.

[00161] Preservatives [00162] Preservatives will be used in Invention to extend the shelflife of the material, especially when it is stored in untoward conditions such as those that are moist and warm. Such conditions encourage the growth of microbes which may adversely affect the health of consumers. The use of any combination of preservatives cannot be completely relied on to inhibit the growth of all microbes, but what it does provide is a threshold of safety. It should be emphasised that the use of a preservative is not intended to compensate for poor sanitation. Good Manufacturing Practice dictates that all procedures associated with the manufacturing of any food related article must be carried out in a sanitary manner. It is in the best interest of all parties to main good hygiene, so care must be taken that the articles are adequately packaged and stored in a suitable environment. However sometimes unpredictable situations occur. There is also no guarantee how the food contact articles (Compostable tableware) will be treated once the product is sold. It is therefore imperative that preservatives are used in the material Invention.

[00163] The effect of a low pH against microbes was the synergistic effect of organic acid in enhancing the antimicrobial activity of the preservative it is paired with. Potassium sorbate paired with citric acid is well documented to be effective. The preference toward citric acid was previously explained. The rest of this section will highlight the main reasons potassium sorbate was chosen.

[00164] Potassium Sorbate has held a good safety record since its antimicrobial properties were recognised in the 1940s, which has led to its widespread use in food, pharmaceuticals and cosmetics since it became commercially available in the 1950s. It is known as food additive E202. It is classified as GRAS (generally recognised as

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PCT/AU2017/051257 safe) and in the case of FDA regulations, GRAS substances are exempt from regulation as an indirect additive in food contact materials/articles. The FDA describes indirect additives as anything that migrates into food from a food contact material/article. This means that Potassium sorbate is exempt from indirect additive regulation. However, underGood Manufacturing Practice guidelines, the allowed limit of potassium sorbate (and all other additives) is the amount necessary for adequate function. For Invention, this is estimated to be between 0.1% JO.2% by weight.

[00165] Potassium Sorbate in its crystal form is inactive, but with the addition of water it undergoes chemical change into its active form sorbic acid. In fact, potassium sorbate is referred to as the most soluble form of sorbic acid. Its high solubility in water means it can be dispersed more effectively. Heat increases the solubility of potassium sorbate.

[00166] Sorbic acid also requires a low pH of <3 to be most effective. Potassium Sorbate is generally more effective against yeasts and moulds than bacteria, but this isn't a negative aspect since yeasts and moulds can survive in extreme pH conditions. Bacterial growth is generally inhibited below pH 4.0, and a pH level of 2.0 g.O will be used for the material of the compostable tableware. For sorbic acid, a concentration that yields pH 2.0 g.O (when mixed into what is being preserved) is adequate against many yeasts and moulds.

[00167] Cross linking agents [00168] The purpose of using a reactive cross-linking agent in the material Invention is to enhance its structural strength.

[00169] The cross Jjnking of starch refers to the bond formed between one polymer chain and another; it results in a strengthened material. Covalent cross Jinks are mechanically and thermally stable. C ross linking has been shown to reduce the water sensitivity of starch and improve barrier properties. Citric acid cross Jjnked starch films show about 150% higher strength than non gross Jinked films.

[00170] Borax is an effective starch cross Jjnker but its safety is questionable. Its use in food contact materials is heavily regulated and borax must not migrate into the food.

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PCT/AU2017/051257 [00171] A number of substances react with gelatinised starch in its aqueous form to form substance ^tarch cross Jinks. The substance sodium tetraborate (more commonly known as borax) has exhibited promising qualities as a cross lining agent in starch polymer applications. Borax is a short-range cross pinker and reduces molecular slip and uncoiling under stress. In a certain study, 1% of Borax enhanced the ultimate tensile strength ofthe material by 25% and 17.9%. Borax is also a type of preservative. It inhibits mould, but its use is only permitted for certain applications.

[00172] Borax is an inexpensive and efficient cross poking agent, but it is banned by the FDA as a food additive. Borax is listed as a prior sanctioned food ingredient in the manufacturing of paper and paperboard products for food packaging. However Borax is only approved for use as an adhesive and coating, under the condition that it does not migrate into food. Borax is also approved for use in certain food contact coatings and food contact textiles. The FDA has set strict specific limits to ensure that the chance of any migration is very minimal.

[00173] Nonetheless it is questionable to use borax in Invention. Borax is not G RAS (generally recognised as safe), so there is little incentive to use borax when there are alternatives available. When borax is heated, it produces toxic fumes - Invention requires heat curing to fully set. Borax is also mildly toxic when ingested.

[00174] A number of substances are able to form cross J[nks in gelatinised starch but citric acid is the most suitable for use in Invention. Citric acid is not only safe, it is very versatile.

[00175] An alternative cross Jinking agent to borax is citric acid. Citric Acid is classified as G RAS, meaning it is certainly non Jtoxic. It is also a food additive known by the code number 330, commonly found in beverages, preserves, and dairy products. Citric acid has applications beyond food. For example, it is used in pharmaceuticals, cosmetics, and as a metal chelator (ability to donate ions). Citric acid as a chelator is thought to contribute to its antimicrobial properties.

[00176] The citrate component of citric acid is responsible for its ability to form starch cross Jinks. The interaction of starch with citric acid mainly takes place around the branching points of amylopectin.

[00177] Beyond citric acid's usefulness in the material Invention as a cross-linking agent other functional qualities that benefit the material include its antimicrobial

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PCT/AU2017/051257 properties, its acidic properties which lower the pH of the material, and its ability to induce starch acid hydrolysis. All such properties are equally important The fact that citric acid has so many uses makes it a preferable raw material in the material for the compostable tableware.

[00178] Heat assists the forming of cross Jjnks between citric acid and starch.

[00179] Cross Jjnks can be initiated by chemical reaction via heat, pressure, pH or radiation. Citric acid cross linking of starch occurs at high temperatures, suggesting a curing of about 5 min at 165 ^70 eC. However cross puking reaction is initiated at temperatures as low as 70eC and increased with curing temperature at high citric acid content. Invention putty is currently baked at105eC fora number of hours.

[00180] Calculating the optimal amount of cross poking agent is not always straightforward.

[00181] The effect of citric acid cross Jjnks in thin, flexible starch films has found that citric acid cross Jjnked starch films show about 150% higher strength than non cross £jnked films. Concentrations of citric acid less than 5% provided relatively low improvement in tensile (stretching) strength and concentrations above 5% decreased the tensile strength of the films.

[00182] It is generally assumed that the greater the amount of starch cross Jjnks, the more rigid the material becomes. There is a point where the rigidity could turn into brittleness. As mentioned, that at concentrations above 5%, excessive cross Jinks limit the mobility of starch molecules, leading to lower tensile strength. Tensile strength is important in flexible bioplastics but in the case of Invention, a rigid bioplastic is the goal.

[00183] The more citric acid, the more cross-links present in the gelatinised starch structure; it is convenient to generalise that this would theoretically result in a harder material. However excess un-reacted citrate has also been observed to act as a plasticising agent. The addition of more cross-linking agent does not always result in a more rigid material, especially when all the cross-linking sites have been occupied. This phenomenon was observed in some embodiment material samples. Depending on the amount of citric acid added, this phenomenon may mean that the resulting material is strong yet flexible. The rigidity is also dependant on the amount of plasticiser added to the material.

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PCT/AU2017/051257 [00184] Invention test formulas currently range between 2.0% p0.07% citric acid, but 0.2% g.02% is found most suitable.

[00185] Despite known findings to the contrary, it is believed that this amount is sufficient to cross ffnk the starch contained in Invention. Invention material samples containing 2% citric acid (by total material weight) were very flexible, indicating that all the citrate ptarch cross pnkpites had been occupied and there was enough free citric acid in the material to act as a plasticiser. Samples containing between 0.2% ft 0.02% citric acid were the most rigid, likely owing to the cross Jjnks.

[00186] Plasticisers [00187] The purpose of using a plasticiser in the material Invention is to reduce brittleness. There are currently three raw materials in the material Invention that can act as a plasticiser: Glycerol, citric acid and potassium sorbate. However only one raw material has a sole purpose of being a plasticising agent: Glycerol.

[00188] The amount of glycerol used in the material for Compostable tableware application (compostable food vessels) needed to result in a material that was still mostly rigid, but not brittle. This required a number of experiments to test different ratios.

[00189] Itwas found thatlnvention material samples with a high amount of glycerol became very flexible but tough, akin to leather; it could be suitable for another application. After all, the applications for Invention should not be limited to food contact articles in the form of vessels.

[00190] Glycerol is the only raw material that has been added to Invention with the sole purpose of being a plasticising agent.

[00191] Glycerol (also known as glycerine) is a type of sugar alcohol. Other sugar alcohols such as sorbitol can be adequately substituted in place of glycerol as a plasticising agent. Glycerol was chosen because of its widespread use as a plasticiser in literature pertaining bioplastic films, which proves its efficacy. Glycerol is also the most widely available and most cost effective.

[00192] The hardness of Invention is due to retrograded gelatinized starch, which relies on water being drawn out of the cooked starch. Glycerol is a humectant Its hydrophilic nature means it attracts and retains moisture. The way glycerol works as

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PCT/AU2017/051257 a plasticiser is that it embeds itself between the starch polymers, allowing them to move even once the starch has retrograded. Glycerol acts like a lubricant at the molecular level by reducing friction. The more glycerol (or other plasticiser) added, the less brittle and more flexible the retrograded starch (or cured material) becomes.

[00193] P re Existing research on thin, flexible bioplastic films showed that glycerol appeared to have an anti plasticising effect at low concentrations. It has been found that little was enough to plasticise a film, as long as glycerol preferentially occupied water binding sites during film formation. It was commented that anti plasticising effects were only noticed in films with low water content, and that in films with high water content glycerol behaved as a typical plasticiser.

[00194] In some cases, potassium sorbate can exhibit plasticising effects in bio ft plastic structures. Potassium sorbate was found to act as a plasticiser in wheat gluten film. Gluten is a type of protein and starch is a type of polymer. Potassium sorbate might affect polymers in a different way. The efficacy of potassium sorbate as a plasticiser in Invention was yet to be tested.

[00195] However, in experiments the inventor determined that Potassium Sorbate really did induce a plasticising effect on the material samples, which meant that less glycerol was needed. However, this plasticising effect does not render glycerol obsolete; for a reason, glycerol softens the material with less effect on its shearing strength.

[00196] In some cases, citric acid can exhibit plasticising effects in gelatinised starch structures. Its effects are independent to the amount glycerol, but both play an important role in determining the materials physical properties.

[00197] The phenomenon of citric acid exhibiting plasticising qualities has been documented in literature. It occurs when all the citrate fttarch cross ftnking sites have been occupied and there is excess free citric acid. Depending on the amount of citric acid added, this phenomenon may mean that the resulting material is strong yet flexible; and depending on the intended application, could prove to be a useful property. It has been observed in independent experiments.

[00198] The experiments referred to, was when a sets of different Invention material test samples containing various concentrations of glycerol were analysed for brittleness, rigidity and plasticity. Some sample sets contained different amounts of

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PCT/AU2017/051257 citric acid. The analysis was not quantitative, but rather a qualitative comparison between the samples; each sample was bent and twisted to the point of breakage. The first intent was to find a test formula that satisfied the condition of being both relatively rigid, but not brittle. The second intent was to gauge how the material felt in the hand as the resulting product will likely be hand held by the consumer when used. [00199] The analysis occurred overa period of five days and it was observed that the material became progressively less brittle and more flexible. It was found that the middle range of citric acid resulted in a rigid material; the extreme low and high ranges resulted in a more flexible material. The overall trend that indicates that the more glycerol added, the more flexible the material becomes. Citric acids plasticising properties does notmean it can replace glycerol in Invention. Nonetheless citric acid s ability to plasticise starch in certain conditions needs to be kept in mind.

[00200] To further elaborate upon the previous subsection, the following physical properties have been observed for Invention material samples containing a certain amount of glycerol and citric acid. Existing research on thin, flexible starch films found that the addition of glycerol affected tensile strength and elongation of cross Jinked starch films. Both the control (no citric acid) and cross Jinked films with less than 10% glycerol became brittle after curing. Increasing the concentration of glycerol to 15% provided the best tensile strength and increased elongation, resulting in flexible films. At concentrations above 15% the plasticising effect was too pronounced and made the starch molecules move easily, leading to high elongation but decrease in tensile strength.

[00201] T esting [00202] Experiments conducted on the material ofthe compostable tableware of the invention mostly affirmed the observations.

[00203] During the experiments the ratio of glycerol was varied. For some material sample sets, citric acid was added. Nearly all the material samples were brittle when they were initially removed from the oven, the exception being the samples containing 12.8% J5% glycerol. The samples were observed over five days and each sample was tracked for weight gain and change in physical properties. All samples became less brittle after five days, mostly due to absorbing some moisture reflected in a slightly increased weight. The samples mostly equalised in moisture content to about

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PCT/AU2017/051257

4% )(10% total moisture. It was found that a greater amount of glycerol correlated with greater flexibility. The amount of citric acid added to the material also influenced its rigidity; the pattern is more complex than glycerol, but predictable once the trend is understood.

[00204] Compostable tableware material samples containing 0.6% glycerol were generally the most rigid, but also the exceedingly brittle.

[00205] F urther tests were not carried out with the addition of citric acid.

[00206] Compostable tableware material samples containing approximately 4% )( 5% glycerol were brittle on the initial day. As a whole they were less brittle than the samples containing less glycerol. After five days the material had become less brittle, dependant on the amount of citric acid in the material:

[00207] Material samples containing 5% citric acid (pH 2.0) were not brittle at all. The samples were very soft and flexible, likely owing to an excess of un Reacted citric acid in the material; all the citrate ^tarch cross ffnk sites were occupied. The material sample was slightly leathery.

[00208] Material samples containing between 0.33% g.05% citric acid (pH 2.0 j] 3.0) were generally the most rigid of the subset. The samples were rigid, but slightly springy when flexed. The samples were still slightly brittle but rather resilient; they only snapped when bent to an angle of approximately 90 degrees. At 0.05% citric acid the material seemed the least brittle.

[00209] Material samples containing between 0.03% )(0.01% citric acid (pH 3.5)( 4.0) were not brittle. Both samples were very soft and flexible.

[00210] Compostable tableware material samples containing approximately 9% )( 10% glycerol were brittle on the initial day, but less so than samples containing less glycerol. After five days the material was less brittle, and some samples were not brittle at all. The flexibility of the samples were affected by the amount of citric acid in the material:

[00211] Material samples containing between 0.33%-0.05% citric acid (pH 2.0 3.0) were the most rigid of the subset. The samples were mostly rigid, and slightly springy when flexed. They were less rigid than those in othersubsets containing more

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PCT/AU2017/051257 glycerol; some ofthe samples were able to bend to an angle of 180 degrees and not snap. At 0.05% citric acid the material seemed the most rigid.

[00212] Material samples containing between 0.33% g.05% citric acid (pH 2.0 3.0) were the most rigid ofthe subset. The samples were mostly rigid, and slightly springy when flexed. They were less rigid than those in other subsets containing more glycerol; some ofthe samples were able to bend to an angle of 180 degrees and not snap. At 0.05% citric acid the material seemed the most rigid.

[00213] Material samples containing between 0.03% JO.01 % citric acid (pH 3.5 J 4.0) were not brittle. The 0.03% sample was very soft and flexible. At 0.03% sample was the most rigid ofthe subset.

[00214] Compostable tableware material samples containing 10% $2% glycerol were only slightly brittle on the initial day. As a whole they were less brittle than the samples containing less glycerol. After five days the material had become less brittle, dependant on the amount of citric acid in the material:

[00215] Material samples containing 5% citric acid (pH 2.0) were not brittle at all. The samples were very soft and flexible, likely owing to an excess of un Reacted citric acid in the material.

[00216] Material samples containing between 0.33% g.05% citric acid (pH 2.0 J 3.0) were the most rigid ofthe subset, but only slightly, due to the amount of glycerol present. The samples were not brittle at all. They were soft and flexible, yet tough to tear. At 0.33% citric acid the material seemed the most rigid.

[00217] Compostable tableware material samples containing 12% J5% glycerol were hardly brittle at all on the initial day. As a whole they were noticeably less brittle than the samples containing less glycerol. The material became very flexible afterfive days. It is too flexible for application as Compostable tableware food vessels, but could have potential for other applications. The effect of citric acid was not tested.

[00218] The current amount of glycerol used in Invention material test formulas range between 0.6% J13% by total weight, but 4% J9% is considered to be a more suitable range for Invention intended for the compostable tableware application. Between 4% J9%, the resulting material exhibits a balance between adequate rigidity

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PCT/AU2017/051257 and minimal brittleness, depending on the amount of citric acid present in the material:

0.33% $.05% citric acid (pH 2.0 $.0) is preferred.

[00219] Examples [00220] Above is outlined the method of preparation for the material, outlines 5 formula iterations under consideration at different development stages. The formulas below are examples of the compostable tableware material and are for explanation only they may be subject to change.

[00221] Example 1

The first formula iteration of the compostable tableware material Moducu : PH 2.0 and 0.06% glycerol by weight
	6g	63.3g
Potato starch	30g	311.6g	31.16%
Vinegar	45ml /45.27g	468.2ml /470.2g	47.02%
(1% Glycerol Solution)	(see below)	(see below)	(see below)
Glycerol	0.05ml/ 0.06g	0.48ml / 0.60g	0.06%
Water, from municipal tap	14.95ml	155.3ml	15.53%

[00222] Example 2

The second formula iteration of the compostable tableware material Moducu : PH 2.0 and 5.0% glycerol by weight
		Μ·»»!
Potassium sorbate, tzuz Citric Acid, E330	U. I log 0.098g	z.Uug 1.69g	U.ZUUu/o 0.169%
Glycerol 1ml/ml	2.302ml/2.904g	39.64ml/50.00g	5.000%
Potato Starch powder	16.000g	275.49g	27.549%
Cornhusk fibres, dry	3,000g	51.65g
Water, from municipal tap	35.961 ml/g	619.17ml/g	61.917%

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PCT/AU2017/051257 [00223] Examples

The third formula iteration of the compostable tableware material Moducu : PH 2.0 and 7.5% glycerol by weight

Potassium sorbate, E202 Citric Acid, E330	0.117g 0.094g	z.Oug 1.61g	0.200% 0.161%
Glycerol 1ml/ml	3.469ml/4.375g	59.46ml/75. OOg	7.500%
Potato Starch powder	16.000g	274.25g	27.425%
Comhusk fibres, dry	3.000g	lllllilllllllll	5.142%
Water, from municipal tap	34.754ml/g	595.72ml/g	59.572%

[00224] Clearly these are examples of corn husks versions but are not limiting of the invention. It shows the range of variability but the importance of the combination to provide a synergistic effect. A compostable tableware of the invention follows the general approach of Figure 4 in which the process 130 includes:

a) Step 131 of combination of material

b) Step 132 of chemically treating by ingredient selection so as to effect crosslinking with flexibility and mouldability

c) Step 133 of physical treating of using the mouldable material or putty to form required shaping;

d) Step 134 of Heat treating to cure or form syneresis

e) Such that step 135 results in a shaped tableware with the body of the tableware formed substantially from decomposable material wherein the compostable tableware can be used as a tableware for supporting food.

[00225] Defining quantity ranges for each of the six ingredient categories + factors to consider:

(1) Water, (2) Starch, (3) Waste Fibres, (4) Organic Acid,

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PCT/AU2017/051257 (5) Plasticiser, (6) Preservatives [00226] There is a preferred specific amount for each ingredient but beyond that it is possible to define a narrow range of ingredient quantities to describe a general formula_ for the material invention. Of course, there are limits to the upper and lower ranges of each material. In the descriptions to follow in the next pages, it will be clear how adjusting the amount of one ingredient can affect the effect of others.

[00227] The percentages listed are strictly by weight not volume (that's why it seems that very little cornhusk is used, but going by visual volume in the cured material its more like 50%) [00228] Water, Temperature and Process [00229] WATER [00230] Water generally refers to added water, unless other ingredients are very wet; and in that case the moisture levels would need to be taken in to account Sometimes the water is added with a dissolved solute, such as citric acid.

[00231] The range for water atthe start of the mixing process before heat exposure is: 50% to 70% [00232] The exact amount of water depends on how large of a batch is used. For example, if you re making a <1 kilogram test batch you might need less water as it would take less time for the starch to gelatinise, and therefore there will be less opportunity for water to evaporate in the interim. On the other hand it would take longer to mix 50 kilograms; a bigger vessel and presumably more surface area (you need space in the vessel to mix) leads to more evaporation.

[00233] LINK TO TEMPERATURE AND PROCESS [00234] The amount of water that gets evaporated also depends on the intensity of the heat source used when gelatinising the starch. Preferably a temperature range for use during the mixing/starch gelatinisation process: at least 52.5eC and not exceed 80eC.

[00235] On the other hand, there is another range for the amount of water present

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PCT/AU2017/051257 in the material after it has undergone the drying/curing process. This affects the immediate hardness and flexibility of the material when it is removed from the oven. If the material is leftto sitout; it will eventually take up some moisture from the immediate environment and become more flexible; sometimes it can even become too flexible to be suitable for use as rigid tableware. (NOTE this is mostly dependent on the amount of plasticiser used and not fully reliant on the level of remaining moisture though both are somewhat interconnected). This scenario and others (another described in the starch section) is taken into account in the following: The range for remaining moisture is after drying/curing is: 4% to 10% [00236] The temperature range for the drying and curing process is 105eC to < 200eC. This range is broader than what has been previously stated; suitable temperatures do depend in part on the moulding process and apparatus used. For example, if the mould is open, a lower temperature such as 105eC is suitable.

[00237] For a two-part mould, higher temperatures such as 120-180eC would facilitate quicker drying. In the case of an open mould, when the material is sufficiently dry (the form has hardened), the temperature could be raised up to 200eC. It is important that the temperature used will not cause one part of the of the moulded material invention to dry faster than another part, otherwise warping will occur. It is to do with an influx of steam trying to escape the material and causing air pockets. However, this would be less of an issue if the material is moulded and cured in a 2-part closed mould with in-built vent holes for steam to escape.

[00238] Improvements can also be made by a simple change in process, described below:

c To ensure less warping: It is also possible that only half of the starch be added to the mixture during the mixing /gelatinisation process.

c No change to ingredient ratios is required; simply an altered production process. It would be safer to get the mixture down to 45eC to give a buffer.

c When the material is moulded, less water would need to be driven off as some of it would be used to gelatinise the starch that was added afterwards. As the water leaves the mould, the void left behind would be filled by the expanding starch. For this initial mixing process, the rest of the starch powder is incorporated and left ungelatinised.

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PCT/AU2017/051257 t To prevent the powdered starch gelatinising too early, the temperature of the mixture should not exceed 50eC. The reason is because the gelatinisation of potato starch starts ata temperature as low as 52.5eC. It would be safer to get the mixture down to 45eC to give a buffer.

t When the material is moulded, less water would need to be driven off as some of it would be used to gelatinise the starch that was added afterwards. As the water leaves the mould, the void left behind would be filled by the expanding starch.

[00239] Starch [00240] The range for starch is fairly narrow. Gelatinised starch can be classified as a biopolymer, and is what holds everything together. As such its primary function is referred to as the binder. The key here is having the right amount of starch, and this amount ties in closely to the amount of water present in the mixture.

[00241] The following defines the upperand lower limit of water in relation to starch: [00242] The water to starch ratio must be so that there is enough water to fully gelatinise the starch in the mixture. The ratio can then be adjusted to account for the amount of water that is inevitably lost to evaporation during the initial gelatinisation process. In addition, there must also be enough water so that the starch mixture is loose enough for mixing; this allows for all the raw materials to be thoroughly incorporated.

[00243] Beyond thatthere is no benefit in adding more water. There is a point where increasing the ratio of waterto starch is a detriment Whatever waterthat is added must eventually is taken out via evaporation; the more water there is, the longer it takes to evaporate and the more energy it takes.

[00244] Aside from matters of time, energy and cost there are other matters to consider. Excess water negatively affects the strength of the material. To elaborate: During the initial starch gelatinisation process, starch granules absorb water and increase in size. The more waterthat is added during the initial starch gelatinisation process, the more the starch molecules increase in size. When the shaped gelatinisedstarch-putty is heated during the processes of drying and curing, the gelatinised starch molecules undergo syneresis whereby expels water and hardens. When water is expelled from the starch-putty, it shrinks. The more water initially added, the greater the potential for shrinkage. The more potential there is for shrinkage, the greater the

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PCT/AU2017/051257 chance that the material may warp orcrack.

[00245] It has been explained that the upper limit of starch added to the mixture depends on the amount of water present. The other factor to consider is the ratio of starch to waste fibre.

[00246] There only needs to be enough gelatinized starch in the mixture to hold all the fibres in place. It is not necessary to add more starch to the mixture. Adding more is not detrimental to the structural integrity of the material (assuming the correct water ratio), so why is more starch not necessary? The answer lies in the intention of this material: to hero the use of waste from primary processing. It's about giving waste products such as cornhusk, rice husks, etc a useful purpose. For cornhusks and rice husks specifically, it is not possible produce a vessel using those waste products alone that offers the same functionality as this present Invention.

[00247] The range forstarch is 25% to 30%. This range is slightly broaderthan what was specified before, but only by two percent both ways.

[00248] Starch can also be produced as a bi-product from primary processing; the washing of cut potatoes for example. However starch is much more expensive than natural waste fibres, therefore from an economic perspective it makes sense to only use as much as is necessary to achieve the desired function.

[00249] The use of potato starch is not merely a choice but a preferred approach that gives an unexpected improved effect. Potato starch produces a stronger material, which is beneficial to the environment as it is less resource intensive and can be obtained as a byproduct Wheat starch produces similar results but since it is a wheat product it can be hard to guarantee that is free from gluten and this can be of concern for people who have celiac disease because only a tiny amount of cross-contact can result in a flare-up. Conversely, sensitivity to potato products is very rare. Tapioca starch is also a possible second contender function wise, but cost wise it is not as suitable. Corn starch is very much out of the question; it may be common and inexpensive, but it yields a comparatively more brittle material.

[00250] Potato starch has three substantial benefits including being:

t environment wise, t health and safety wise, and

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PCT/AU2017/051257 c most importantly product performance.

c Natural waste fibres from primary processing [00251] Examples include, but are not limited to: corn husk, corn silk, rice husk and sugarcane pulp.

[00252] The upper limit of waste fibres used is bound by the amount of start present in the mixture. The point of saturation is where the gelatinised starch cannot fully envelope and hold all the fibres together. If the point of saturation is exceeded, then the material will be brittle and break apart easily.

[00253] The upper limit of waste fibres is 10%, and the lower limit of waste fibres is 2%, referring to percentage by weight (The usage in the current preferred embodiment is between 5-6%) This percentage by weight is for fibres that are dry. The meaning of 'dry_ in this case does not mean the complete absence of moisture; it means that the cornhusk is not obviously damp. If using wet fibres, the percentage of moisture in the fibres would be accounted for as water content [00254] The lower limit of waste fibres is guided by its function as a strengthening agent Fibres are able to increase the shearing strength ofthe material because they branch out and become entangled with the gelatinised starch.

[00255] In the examples there is a Length x Width ratio of 1:4 and 1:10, with the current ratio used being 1:10. The fibres would probably best remain in a scale between 1:4 and 1:30, with the preference fora ratio within the middle ranges.

[00256] The preference for cornhusk is not merely choice; cornhusk has particular advantages. When cornhusk is observed under magnification, its uniquely rough texture becomes apparent; there are little hairs on the surface of cornhusk, as well as ridges and peaks. This extra surface area works in favour of a stronger material as there is more for gelatinised starch to cling to. Therefore cornhusk has a definite advantage over other waste fibres.

[00257] The effectiveness of the waste fibres as a strengthening agent is also determined by the length-to-width ratio ofthe fibres. The fibres need to be longer than they are wide. In essence, a longer fibre promotes a stronger material as better ensnares to the gelatinised starch. If the fibres are too short ortoo small in scale, then it will be ineffective as a strengthening agent; this marks the lowersize limit ofthe fibres.

WO 2018/090087

PCT/AU2017/051257 [00258] There is an upper size limit to the fibres. It the fibres are too large in scale (no matter what the ratio), the gelatinised starch won't be able to properly envelope it and therefore will be unable to hold on to it. If the gelatinised starch cannot hold the fibres securely, the resulting material will be unsatisfactory in quality and unfit for use;

the material will fall apart and the surface will be rough where the fibres stick out.

[00259] An advantage is that the material invention product biodegrades more readily compared to other products in the same market category. A bigger and longer fibre strengthens the material better than a smaller and shorter one. Therefore, there is a lower size limit where fibre ceases to be effective.

[00260] The size ratio of the waste fibres is between 1:5 and 1:30.

[00261] The following specifies the minimum and maximum length of the fibres. The corresponding width is dependent on the specified ratio. The maximum length is 15 mm, and the minimum length is 5mm. This size guide is only applicable when the material is used to make food vessels. This size guide ensures thatthe overall scale of fibres is suitable for the scale of the end product [00262] Organic Acids, specifically citric acid [00263] Primarily this is acetic acid and citric acid. Citric acid is preferred because it is able to work synergistically with both starch and the preservative potassium sorbate. It can be said that this synergy produced an un-expected result.

[00264] Acetic acid has its merits, but far fewer benefits. The advantage acetic acid has over citric acid is that it is effective in inhibiting mould. It is also more effective against a wider range of microorganisms. However, the downside is that acetic acid has a pungentsmell which citric acid lacks, and acetic acid may impartan objectionable taste.

[00265] It is an idea to use both acetic acid and citric acid to fight microorganisms in Invention, but in reality this approach does not work favourably for the material as a whole. It must be considered that acid plays a number of roles in Invention, and a delicate balance must be achieved otherwise the material will fail. To explain further: If both acetic acid and citric acid is to be used together to fight microorganisms, there must be an effective amount of both acids present in the material. The conundrum is that when there is enough of both acids to effectively fight microorganisms, there arises

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PCT/AU2017/051257 a potential issue of the gelatinised starch becoming overly degraded via excessive acid hydrolysis. The result of excessive acid hydrolysis on gelatinised starch is one big, useless, sticky mess. Therefore, it is not recommended to use both acids at once.

[00266] Synergy between citric acid and starch:

[00267] Citric acid lowers the pH level to enable acid hydrolysis. This is true of acetic acid and all other acids. The minimum acidity required for this is pH 4 [00268] To a certain extent, the citrate component of citric acid is able to form starchcitrate bonds. If there are enough stare h-citrate bonds then the material becomes more rigid. However, an increased amount of starch-citrate bonds does not necessarily result in a stronger material; too many bonds may result in an overly stiff and brittle material (especially if there is insufficient plasticiser present).

[00269] On the contrary it is a different situation if there is a great excess of citrate. If all the available starch binding sites have bonded with citrate and there is excess citrate in the mixture, this excess citrate can roam freely and can act as a plasticiser. This plasticising effect has been observed by the inventor in material samples made with a large amount of citric acid, whereby the material samples were comparatively more flexible than those made will less citric acid.

[00270] Citric acid is not used in Invention specifically as a plasticiser, but its potential plasticising effects must be considered. The currently preferred embodiment of Invention utilises citric acid, and the amount of glycerol plasticiser used has been tailored accordingly. However if for any reason acetic acid is used instead of citric acid, it is necessary to increase the amount of glycerol slightly.

[00271] Synergy between citric acid and the preservative potassium sorbate:

[00272] Studies have shown that citric acid has bacteriostatic properties. Citric acid also enhances the effectiveness of the preservative potassium sorbate by lowering pH. The following table shows the effect of pH on potassium sorbate.

[00273] The effect of different PH levels on the activity levels of sorbic acid/potassium sorbate

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PCT/AU2017/051257 [00274]

The effect of different PH levels on the activity levels of sorbic acid / potassium sorbate
i PH 3	98%
| PH 4	85%
PH 5	37%
i PH 6
PH 7	0%

[00275] Plasticiser, specifically Glycerol (also known as glycerine) [00276] Glycerol is used as the plasticising agent The range for the plasticiser glycerol is between 0.6% and 9%.

[00277] For the current preferred embodiment an amount of approximately 5% of glycerol is used. Beyond 9% glycerol the resulting material samples are not rigid enough to create functional vessels (for food application use); the result is a flexible leathery material that would be useful other applications - after all the material should not be limited to food contact use. The material with 0.6% added glycerol has the potential to be too brittle if the material is very thin. However, when made into a bowl at an appropriate thickness of >1 mm, it is only a concern if the end user purposely sets outtosnapit For normal, use it is not a concern.

[00278] Preservatives, specifically Potassium Sorbate [00279] The reasons forchoosing Potassium Sorbate in a nutshell is thatPotassium Sorbate has an excellent safety record as a preservative used in food. The logic is that if it is safe to ingest in food, then what little amount that's used in the Compostable tableware poses a negligible risk. Apart from safety, the other benefit of using Potassium Sorbate is that its effect as a bacteriostatic agent is enhanced by the presence of citric acid a component present in the Compostable tableware material.

[00280] The form of potassium sorbate used is the pure powdered or granulated form. The minimum amount of potassium sorbate added is based on how much is needed to be effective. The upper limit is governed by Good Manufacturing Practice. [See regulation (EC) No. 2023/2006], Set by the EU, GMP governs the suitability of

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PCT/AU2017/051257 raw materials to be used, and specifies criteria that ensure the manufacturing process used result in a product that is safe and suitable for food contact In terms of additives with G MP status, EU regulations mandate that no more be used than required to fulfil the technical purpose in the material. In terms of antimicrobials, the EU regulations require that the antimicrobial substance used in a food contact material not show any effect on the food itself.

[00281] According to one specific study an effective combination was 0.15% citric acid and 0.1% potassium sorbate, which inhibited growth of approximately 60% of bacterial isolates, including the two additional spiked bacteria. Taking all that into account the range for potassium sorbate is preferably: 0.15% - 0.6%, [00282] Not a lot of potassium sorbate is needed to be effective in the material. The current amount of potassium sorbate used in the preferred embodiment is 0.2%. The specified limit of 0.6% by weight is really not much, but its possibly a little more than what is needed. However, there is a specific reason for specifying an amount that is a little more than needed in the end product This extra amount accounts for the fact that potassium sorbate can sublimate in heat. Therefore, it is very possible that a portion of what was added will disappear during processing; exactly how much is dependent on the intensity and time of heat exposure. It is important to note that despite specifying more potassium sorbate to be added initially, the end amount of potassium sorbate that remains in the material is only how much is required to do the job well. Therefore, the amount of added potassium sorbate remains complainant to the limit set by GMP (Good Manufacturing Practice).

[00283] Potassium sorbate has a distinct smell and taste butatthe amounts added, the effect is minimal. At the amounts specified in the preferred embodiment of Invention, it is very unlikely that potassium sorbate will impart taste or smell taint to food.

[00284] The following charts demonstrate the taste and olfactory effects of adding different amounts of potassium sorbate, citric acid, and glycerol. Note that the amount of potato starch in each sample remains the same. Whatis written in the charts is purely subjective, and in no way substitutes official tests that would be made by any relevant governing authority (such as the USA FDA).

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SubjectiveTaint Observations: Direct Olfactory Testing of Moducu CompostableTableware Material SampleSets L1, L2and L3

	Mg»·
Citric Acid (C.A.) crystalline salt	100%	(Control) Like lemons and other distinctly sour citrus fruits. Fresh, pleasant and very mild. L) nobtrusive.
Potassium sorbate (P.S.) in dry powder form, a 3 teaspoon	100%	(Control) A mild smell that is mostly sweet. Not very acrid or sour at al I compared to its sorbic acid counterpart.
Glycerol (GLY.)	100%	(Control) Slightly sweet smell, very mild and unobtrusive.
Potato starch	100%	(Control) Smells I ike freshly cut potatoes. Earthy. Very mild and unobtrusive.
Cornhusk	100%	(Control) Smells 'green, and somewhat grassy with undertones of corn. A rather pleasant earthy smell that is unobtrusive.
Sample L 1.1 Sample L2.1	P.S.: 0.2% C.A.: 0.169% GLY: 5.0% P.S.: 0.2% C.A.: 0.161% GLY: 7.5%	A11 the L1 set sampl es contai ned the same amount of potassium sorbate. As such, no discernible difference between the three samples could be detected when conducting the olfactory (smell) test. The smell of potassium sorbate dominates, but the least strong of the three ex peri ment L sample sets.
Sample L3.1	P.S.: 0.2% C.A.: 0.155% GLY: 10.0%	Overall the smell is not entirely unpleasant or overpower! ng, but the scent of potassi urn sorbate definitely dominates. T he smelI is not obvious unless the samples are sniffed in close range of <2cm. T he smel I of the other ingredients could not readily bedefined, but perhaps a slight smel I of the cornhusk could be detected.
Sample L 1.2 Sample L2.2	P.S.: 0.6 % C.A.: 0.169% GLY: 5.0% P.S.: 0.6% C.A.: 0.161% GLY: 7.5%	AII the L2 set samples contained the same amount of potassium sorbate. As such, no discern! ble difference between the three samples could be detected when conducting the olfactory (smell) test. The smell of potassium sorbate domi nates; more so than sampl e set L1, but less so than sample set L3.
Sample L3.2	P.S.: 0.6% C.A.: 0.155% GLY: 10.0%	Overall the smelI is not entirely unpleasant or overpower! ng, but the scent of potassi urn sorbate defi nitely domi nates. T he smel I is not obvious unless the samples are sniffed in close range of <5cm, but of course the less smel I the

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Sample L 1.3 [00285] Sample

L2.3 [00289] Sample

L3.3

P.S.: 1.0%

C.A.: 0.167%

GLY :5.0% [00286] P.S.:

1.0% [00287] C.A.:

0.160% [00288] GLY:

7.5% [00290] P.S.:

1.0% [00291] C.A.:

0.154% [00292] GLY:

10.0% better. T he smel I of the other ingredients could not readily be defined.

AII the L3 set samples contai ned the same amount of potassium sorbate. As such, no discern! ble difference between the three samples could be detected when conducting the olfactory (smell) test. ThesmelI of potassium sorbate dominates; more so than both sample sets L1 and L3.

Overall the smelI is not entirely unpleasant or overpower! ng, but the scent of potass! urn sorbate def! nitely is the strongest of the three sample sets. T he smel I is not too obvious unless the samples are sniffed In close range of <5cm, but of course the less smell the better. The smel I of the other i ngredients could not readily be def!ned as the potassium sorbate smel I domi nates.

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SubjectiveTaint Observations: Direct Taste Testing of Moducu Compostable Tableware Material Sample Sets L1, L2andL3

Citric Acid (C.A.) crystal line salt form, a 3 teaspoon	100%
Potassium sorbate (P.S.) in dry powder form, a 3 teaspoon	100%
Glycerol (GLY.) a teaspoon	100%
Potato starch, a teaspoon	100%
Cornhusk, a teaspoon	100%
Sample L 1.1	P.S.: 0.2% C.A.: 0.169% GLY: 5.0%
Sample L2.1	P.S.: 0.2% C.A.: 0.161% GLY: 7.5%
Sample L3.1	P.S.: 0.2% C.A.: 0.155% GLY: 10.0%
Sample L 1.2	P.S.: 0.6 % C.A.: 0.169% GLY: 5.0%
Sample L2.2	P.S.: 0.6% C.A.: 0.161% GLY: 7.5%

(Control) Extreme sourness that tasted salty. After ri nsi ng mouth out, there was sweetness and then a strong metallic aftertaste.

(Control) A very mild taste that is more bitter than sour. The aftertaste is sweet. Over the taste is not entirely unpleasant given the amount of P.S. directly placed in the mouth. In a conventional setting only a small fraction of the amount would be put in the mouth when mixed with other ingredients.

(Control) A bit like watered down honey. Slightly viscous in the mouth and tastes mildly sweet, but not enough to be consi dered a sweetener.

(Control) Tastes like potato, but with a sweet u ndertone. T hi s i s not surpri si ng si nee starch i s a type of carbohydrate polymerwhich breaks down i nto sugar.

(Control) Tastes a bit 'green, and grassy with the scent of corn, but not at al I sweet. Could be described as slightly herbaceous but the taste is mild.

AII the L1 set samples contained the same amount of potassium sorbate, cornhusk and potato starch, but differing amounts of C.A and GLY. No difference was tasted between the three samples. Nothing could be tasted until the L1 samples were chewed. The taste was mostly sweet, but this sweetness was very mild. The taste potassium sorbate is the most obvious, but there was o hi nt of sourness or bitterness. In the after taste there was a hi nt of grass! ness from the cornhusk. It i s very unlikely that any noticeable taste would transferto food-stuffs in contact with Moducu material made accord! ng to L1 specifications, even if the food is high in water or oil content.

AII the L2 set samples contained the same amount of potassium sorbate, cornhusk and potato starch, but differing amounts of C.A and GLY. No difference was tasted between the three samples, but overall they were slightly stronger tasting than the L1 samples. Nonetheless nothing could be

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Sample L3.2 i tasted unti I the L 2 sampl es were chewed. T he taste i was mostl y sweet, but thi s sweetness was very i mi I d. T he taste potass! um sorbate i s the most i obvi ous, but there was o hi nt of sourness or

P.S.: 0.6% ί bitterness. In the after taste there was a hi nt of C.A.:0.155% < grassiness from the cornhusk. It is very unlikely GLY: 10.0% ί that any noticeable taste would transfer to foodi stuffs in contact with Moducu material made i accord! ng to L 2 spec! fi cat! ons, even i f the food i s i high i n water or oi I content.

Sample L 1.3

Sample L 2.3

Sample L 3.3

P.S.: 1.0%

C.A.: 0.167%

GLY :5.0%

P.S.: 1.0%

C.A.: 0.160%

GLY: 7.5%

P.S.: 1.0%

C.A.: 0.154%

GLY: 10.0%

AII the L3 set samples contained the same amount of potassium sorbate, cornhusk and potato starch, but differing amounts of C.A and GLY. No difference was tasted between the three samples, but overal l they were slightly stronger tasting than the LI and L2 samples. Nonetheless nothing could be tasted untiI the L3 samples were chewed. The taste was mostly sweet, but this sweetness was very mi I d. T he taste potass! um sorbate i s the most obvious, but there was o hint of sourness or bitterness. In the after taste there was a hi nt of grassi ness from the cornhusk. It is very unlikely that any noticeable taste would transfer to foodstuffs i n contact with M oducu materi al made according to L3 specifications, even if the food is [00284] [00285] Interpretation [00286] Embodiments:

[00287] Reference throughout this specification to 'one embodiment, or 'an embodiment, means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases 'in one embodiment, or 'in an embodiment, in various places throughout this specification are not necessarily all 10 referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[00288] S imilarly it should be appreciated that in the above description of example 15 embodiments of the invention, various features of the invention are sometimes

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PCT/AU2017/051257 grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detailed Description of Specific Embodiments, with each claim standing on its own as a separate embodiment of this invention.

[00289] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Different Instances of Objects [00290] As used herein, unless otherwise specified the use of the ordinal adjectives 'first,, 'second,, 'third,, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

S pecific Details [00291] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

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T erminology [00292] In describing the preferred embodiment ofthe invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as forward, rearward, radially, peripherally, upwardly, downwardly, and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

Comprising and Including [00293] In the claims which follow and in the preceding description ofthe invention, except where the context requires otherwise due to express language or necessary implication, the word 'comprise _ or variations such as 'comprises_or 'comprising, a re used in an inclusive sense, i.e. to specify the presence ofthe stated features but not to preclude the presence or addition of further features in various embodiments ofthe invention.

[00294] Anyone ofthe terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

Scope of Invention [00295] Thus, while there has been described whatare believed to be the preferred embodiments ofthe invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope ofthe present invention.

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PCT/AU2017/051257 [00296] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

[00297] Industrial Applicability [00298] It is apparent from the above, that the arrangements described are applicable to the compostable tableware that can be used for one use situations such as take away food industries.

Claims (31)

1. A compostable tableware comprising

a. a shaped tableware;

b. the body of the tableware formed substantially from decomposable material wherein the decomposable material is a natural fibre selected from:

i. Rice husks;

ii. Corn Husks.

c. the decomposable material is held together by processing with

i. a decomposable binder, ii. A form of organic acid

Hi. A form of plasticizer iv. Water

v. Preservatives may be included wherein the decomposable binder is in the form of a gelatinised starch, andwherein the compostable tableware can be used as a tableware for supporting food.

2. A compostable tableware according to claim 1 wherein the product breaks down into constituent natural components such as carbon dioxide, water, inorganic compounds, and biomass at a rate similar to paper, and in form disintegrates into small pieces within months, so that the original compostable tableware is not visually distinguishable in the compost, and leaves no toxic residue.

3. A compostable tableware according to claim 1 further comprising a decomposable food contactable surface on an upper side wherein the compostable tableware can hold food and not affect flavour of food.

4. A compostable tableware according to claim 1 wherein the decomposable food contactable surface is formed by the decomposable material and can hold food and not affect flavour of food.

5. A compostable tableware according to claim 1 wherein the tableware is formed substantially only from decomposable material wherein the decomposable material is a natural fibre.

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6. A compostable tableware according to claim 5 wherein the natural fibre is from cut corn husks in the range of 5 to 15 mm and preferably 7-10 mm long strips and cut against the grain.

7. A compostable tableware according to claim 1 wherein the decomposable food contactable surface is formed by a decomposable layer over the decomposable material allows the user to hold food and the decomposable layer prevents affect flavour of food.

8. A compostable tableware according to claim 1 wherein the decomposable binder is a gelatinised starch.

9. A compostable tableware according to claim 1 wherein the decomposable food contactable surface layer is biologically inert but structurally decomposable.

10. -4 compostable tableware according to claim 8 wherein the gelatinised starch is selected from one or more of the high amylose starches of:

a. potato starch,

b. wheat starch

c. tapioca starch.

11. -4 compostable tableware according to claim 1 wherein the organic acid is selected from one or more of:

a. Citric acid

b. vinegar

12. -4 compostable tableware according to claim 1 wherein the plasticizer is selected from one or more of:

a. Glycerol,

b. citric acid and

c. potassium sorbate

13. A compostable tableware according to any one of claims 1 to 12 wherein ihe tableware is one of:

a. A bowl

b. A plate

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14. A compostable tableware according to any one of claims 1 to 12 wherein the compostable tableware can be used as a food container.

15. A compostable tableware according to any one of claims 1 to 12 wherein the tableware is one of:

a. A shaped handheld open top container

b. A shaped handheld open top container with closable lid wherein the compostable tableware can be used as a single use food container.

16. A compostable tableware according to claim 1 wherein ihe compostable tableware is formed from waste product

17. A compostable tableware according to claim 1 wherein the waste product includes such waste primary products as corn husk

18. A compostable tableware according to claim 1 wherein the waste product includes such waste processed products such as linen fibres

19. A compostable tableware according to claim 1 wherein the waste product includes a combination of such waste primary products and waste processed products.

20. A compostable tableware according to claim 1 wherein the binders holding decomposable material together include gelatinised starches.

21. A compostable tableware according to claim 1 further comprising a compostable tableware formed from waste product including such products as corn husk with or without linen fibres and held together by gelatinised starches that act as binders

22. A compostable tableware according to claim 1 further comprising a compostable tableware formed from waste product including such products allow variability of construction by mouldability and by mixtures of materials and by addition of surface coatings for food segregation and avoid taste contamination

23. A method of forming of compostable tableware including the steps of:

a. A pre-procedure of preparation of waste material being a natural fibre selected from:

i. Rice husks;

ii. Corn Husks.

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b. A procedure of selection of the combination of ingredients for the compostable tableware including a major portion having fibre length substantially in the range of 5 to 15 millimetres to maintain strength

c. A procedure of creating mouldable material

d. A procedure of forming mouldable compostable tableware from mouldable material wherein compostable tableware provides a stable base and allows variability of construction by mouldability

24. A method of forming of compostable tableware according to claim 23 including the step of the Pre-procedure of preparation of waste material including the steps of:

a. Cornhusks are removed from the corncob, or otherwise obtained as a biproduct of other processes requiring corn.

b. The cornhusks are picked and cleaned to remove any dirt and insects.

c. The cornhusks may either be fresh or dried.

d. The cornhusks are cut into 7-10mm long strips against the grain.

e. The cornhusk strips are boiled in vat of hot water for approx. 30 mins until softened and killing any bacteria present.

f. Preferably a preservative may be added at this stage so it has a chance to soak into the husks.

g. The cornhusks are processed with water, sheared until the strips are separated into fibres.

h. processed cornhusks undergoes a process to remove water until about 70% water in weight remains.

i. The pulp is pressed into blocks of equal weight and frozen.

25. A method of forming of compostable tableware according to claim 23 including the step of the selection of the material for the compostable tableware to be formed from a combination of:

a. At least one type of waste material in the form of a natural fibre

b. A binder in the form of a dry gelatinised starch

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c. A form of organic acid

d. A form of plasticizer

e. Water

f. Preservatives may be included

26. A method of forming of compostable tableware according to claim 25 including the step of the selection of the gelatinised starch is selected from one or more of the high amylose starches of:

a. potato starch,

b. wheat starch

c. tapioca starch.

27. A method of forming of compostable tableware according to claim 25 or 26 including the step of the selection of the organic acid is selected from one or more of:

a. Citric acid

b. vinegar

28. A method of forming of compostable tableware according to claim 25, 26 or 27 including the step of the selection of the plasticizer is selected from one or more of:

a. Glycerol,

b. citric acid and

c. potassium sorbate

29. A method of forming of compostable tableware according to claim 23 including the step ofthe Pre-procedure of preparation of waste material including the steps of:

a. If the processed cornhusks will be stored indefinitely, the fresh husks are dehydrated after cleaning.

30. A method of forming of compostable tableware according to claim 23 including the step of pre-processing and combining the ingredients to produce compostable tableware including the steps of:

a. Pre-prepared cornhusk fibres are measured out.

b. The cornhusk is mixed thoroughly with the remaining ingredients.

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c. Preferably including a form of preservative.

d. The mixture is heated over a very low heat with continuous agitation until the starch is fully gelatinised.

31 .A method of forming compostable tableware according to claim 23, including the step of the procedure of forming mouldable compostable tableware from mouldable material, including processing the ingredients to produce shaped compostable tableware comprising the steps of:

a. The compostable tableware putty is manipulated into the required form either by hand or via mechanical means;

b. Using a mould such as a form of compression moulding;

c. The formed compostable tableware putty becomes compostable tableware;

d. baking in an oven at < about 105°C to 120°C until 90% - 95% dry;

e. Packaging and storing in a cool, dry place until it is required;

wherein at the end of its life, compostable tableware can be fully composted.