Improvements in or relating to packaging materials

Abstract

An agricultural waste-based packaging material which may comprise bagasse, may comprise approximately 75% renewable agro waste and 25% softwood pulp. Example compositions are provided including cellul

Description

The present invention relates generally to packaging and particularly, although not exclusively, to packaging materials. The current options for the same or similar applications are either made of plastics materials or wood tree fibre. Plastic materials are considered an enemy of the environment, because they contribute greatly to climate change from the resources used to produce it to the end of life. Usually plastics are disposed of incorrectly as used in the packaging, more often than not going to landfill than recycling. Since it has a non-biodegradable nature, it takes many years to dissolve and sometimes find its way to oceans causing the deterioration of aquatic life. Packaging using wood tree fibre requires cutting a lot of trees which leads to deforestation, threatening the species and ecosystem. Also, cutting trees increases the amount of carbon dioxide in the atmosphere because it removes the ability to absorb this present gas. Solving the plastic problem by moving to paper-based products is therefore just moving from one environmental issue to another. An aspect of the present invention provides a method of forming bagasse-based packaging material, comprising a paper core formed by: i) processing sugarcane to obtain bagasse; ii) de-pithing the bagasse; ii) cooking the bagasse in an alkaline medium; iii) bleaching of pulp; iv) washing of pulp; v) pressing of pulp; vi) transferring white pulp to a paper machine to make paper in thin sheet form having a weightof approximately 35, 40, 50 or 60 g / m2and having technical specifications substantially as defined in Table I; vii) calendaring the paper; and viii) applying a waterborne coating of PLA on both sides of the paper core. A further aspect provides a method to form bagasse-based food packaging material, the food packaging material comprising a paper core formed by: i) processing sugarcane to obtain bagasse base; ii) de-pithing the bagasse; ii) cooking the bagasse in an alkaline medium; iii) bleaching of pulp; iv) washing of pulp; v) pressing of pulp; vi) transferring white pulp to a paper machine to make paper in reel or sheet form having a weight of approximately 35, 40, 50 or 60 g / m2 and having technical specifications substantially as defined in Table I; vii) calendaring the paper; and viii) applying a waterborne, waterproof wax-based coating on both sides of the paper core. The present invention can be used to provide packaging using more sustainable materials made from renewable agro-waste. The present invention allows for the replacement of tree- based or plastic packaging, for example in the food industry. By providing the same benefits of the former to protect products such as food, the present invention adds the feature of being recyclable and biodegradable using agro-based material. In some embodiments the material may be re-pulpable. In some embodiment the fibre length of waste material may be in the range 1.2 -1.5 mm. Combinations of different types of agricultural waste may be used. Some embodiments use a mix of agricultural fibres. Bagasse is the dry pulpy fibrous residue that remains after sugarcane stalks are crushed to extract their juice. It is estimated that about 10 MT bone dry bagasse can be obtained per 10,000 square meters (hectare) of land which ultimately can produce about 4.5 to 5.0 BD MT of unbleached pulp. For every 6,000kg (6.0 tons) of as such bagasse utilized for pulp and paper making about 4,000kg (4.0 tons) of forest wood (as such basis) is saved from felling. The reservation of forest, usage of certified plantation wood (FSC (R.TM) certification) for pulping, application of best available technology, minimum impact on environment, eco-friendly bleaching are some of the key words with regard to the pulp and paper industry. Though several efforts are being made to take care of the environment, the paper industry is still categorized under the red category of the most polluting industries. It is rated to be one of the highly polluting (in top 20's) industries. Bagasse is an important source of raw material for pulp and paper manufacture in the countries that produce large amounts of this type of waste and have scanty wood resources. Bagasse is an excellent raw material for paper making particularly for bleached printing and writing. In view of its ready availability at one point (sugar mill or off site) and the development of various scientific methods for storage and also due to thin walled bagasse fibre and its fibre nature it will produce better consolidated sheet. The bagasse fibre has exhibited the highest fibre bonding potential 96-97% while wood pulp is having 70-88%. Some embodiments are made of sugar cane waste as a base material and provide the same functions as wood-free paper or plastic packaging but with environmentally friendly benefits as the final product is biodegradable and recyclable. Some embodiments, for example, have 28% fewer carbon emissions than conventional packaging. Bagasse Base: • Bagasse is the by-product of the sugar industry and is also one kind of papermaking fibre material. Bagasse is the heterogeneous fibrous residue that remains after sugarcane stalks are crushed for sugar extraction. It is used as a biofuel to produce heat, energy, electricity, and in the manufacture of pulp. Sugar beet agro-waste may be used. The fibre length of the bagasse may be in the range 1.2 -1.5 mm. Sugar beet agro-waste can work better than other types of waste for some embodiments. The fibre length of Bagasse is 1.2 -1.5 mm which is equivalent to Eucalyptus Fibre length of 0.7-1.4 mm which makes the Pulp suitable for papermaking with good strength properties. Examples of the applications for aspects and embodiments of the present invention include: patisserie bags; pharmacy bags; grocery bags; non-food packaging; coffee / sugar packaging. Embodiments of the present invention may, for example, be used for oil and grease resistance purposes in different areas such as food packaging such as burger wrappers and boxes, French fry bags, scoops and cups as well as for other fast food or greasy food containers. It can be used for soap wraps and pet food boxes and bags. The layers may be covered by a waterborne coating that prevents oil and grease penetration and is heat sealable. In some embodiments a water-based coating may be used and can provide the same function as plastic or wood tree paper materials. Aspects and embodiments of the present invention may provide environmental benefits: recyclable, biodegradable and, for example, in some embodiments around 28% fewer carbon emissions than conventional packaging. Embodiments of the present invention may align with a vision of creating sustainable products which are recyclable, biodegradable and have around 28% less carbon footprint than the packaging currently used. The product may be used for oil and grease resistance applications. This may be achieved by using a waterborne coating that has high-performance oil and grease resistance and may have a good heat sealability. Due to its stiffness and strength, it provides excellent packaging performance and enables optimized runnability on high-speed packaging lines. Its soft surface yields quality printing when using flexographic machines. This innovation underlines a vision and goal of developing better and more sustainable packaging solutions for the widest variety of applications. Some embodiments may provide material for boxes and e-commerce packaging. Some embodiments include a coating, for example a coating to provide oil and / or grease resistance. This would make the material suitable for food packaging applications, for example. The present invention may be provided as a paper or paper-based material in thin sheet form. Material formed in accordance with the present invention may, for example, comprise: • 45% - 55% cellulose • 20% - 28% hemicellulose • 20% lignin • 5% sugar • 1% minerals . 2% ash Material formed in accordance with the present invention may, for example, comprise: . 45% - 55% cellulose • 20% - 28% hemicellulose • 20% lignin • 3-7% sugar • 0.5-1.5% minerals . I-3% ash In one embodiment, for example, bagasse pulp may comprise: • 45% cellulose • 28% hemicellulose • 20% lignin • 5% sugar • I % of minerals . 2% ash. Some embodiments concentrate more on cellulose which is the primary extractive of bagasse yield and cellulose characteristics are essential for pulp. Other ingredients may include burnt in a soda recovery boiler or filtered out to be a waste. Examples of the ingredients are shown below. Embodiments of the present invention may be formulated using one or more of the components / ingredients listed and in any combination thereof. Amounts specified herein are specified by way of example and could be within a tolerance of + / - 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% (or other amounts) of that shown. Ash 2% Silica 1% Lignin 21% Pentosan 24% Holocellulose 71% Hemicellulose 29% a-cellulose 42% Phosphorous 0.5% Iron 0.013 Hydrogen 6.5% Nitrogen 0.41 Carbon 46% Oxygen 46% Calcium 0.5% Amounts specified herein may refer to depithed bagasse. Some embodiments include a component of wood pulp. Some embodiments of the present invention comprise a paper or paper-like material (e.g. a coated or uncoated base material). This material may be formed from up to 100% agricultural waste material, for example 50-100%, such as 60-90% or 70-80% e.g. approximately 75%. Some embodiments may include a proportion of wood tree fibre, for example Paper or paper-like material may be made of around 75% sugarcane waste (also known as bagasse) and around 25% of wood tree fibre. This small percentage is added to increase the brightness and strength of the bagasse paper (that by itself can only reach about 80%) to fit its purpose. In some embodiments the product is used for Oil and Grease Resistance (OGR) applications. This may be achieved by using a waterborne coating that has high-performance oil and grease resistance and has a good heat sealability. Advantages of OGR: • Excellent prevention of grease, oil and moisture penetration • Excellent strength providing optimal packaging performance • Optimal runnability on high-speed packaging lines • Quality printing using flexographic machines • Customizable barrier properties • Heat Sealable • Reducing the carbon footprint of transport through flatpack design • Produced from renewable agro-waste raw materials • 28% fewer carbon emissions compared to conventional packaging • Recyclable and biodegradable • Waterborne coating The product is used for Water Barrier Resistance (WBR). This may be achieved by using a waterborne coating that improves water vapour resistance and has a good heat sealability. Advantages of WBR: • Excellent prevention of water and moisture penetration • Excellent strength providing optimal packaging performance • Optimal runnability on high-speed packaging lines • Quality printing using flexographic machines • Customizable barrier properties • Heat sealable • Reducing the carbon footprint of transport through flatpack design • Produced from renewable agro-waste raw materials • 28% fewer carbon emissions compared to conventional packaging • Recyclable and biodegradable • Waterborne coating Examples of applications for WBR include: • Waterproof pouches • Waterproof bags • Flower Wraps • Straws • Waterproof mailing bags • Cups Example Details of how to collect the process and combine all the components: • Typically, from processing 100,000kg (100 tons) of sugarcane in a factory 30,000kg-34,000kg (30-34 tons) of bagasse may be obtained. • Bagasse may be collected from the Sugar Industry and sent to the Paper Mill storage yard. Example Process of Pulping: • De-pithing: It is the process whereby the short pith material is separated from the rest of the bagasse. • Pith needs to be separated from bagasse. • Cooking: Bagasse is cooked by using chemicals in an alkaline medium where the Cellulose is extracted, and the other components are sent to Soda recovery boiler for recovery of chemicals and generating steam. • Bleaching of Pulp: Brown Cellulose - Pulp is bleached by using ECF process to white Pulp. • White Pulp is transferred to Storage tanks of a paper machine to make Paper. Example Process of Paper Making: • Wet End: Sizing chemicals, Starch, Colouring agent - OBA and Dyes, Retention Chemicals are added to Pulp in Wet end. • Press Section and Dryers: Paper is passed through press and dryers to dry the paper. Steam is used to dry the paper which is generated from the Boiler. Example Details of core components necessary for the products: • Cooking Chemicals: Na2S, NaOH, Na2CO3 . Bleaching Chemicals: CIO2, H2O2, NaOH • Paper Machine: Sizing Chemicals Alkyl Ketene Dimer, OBA, Dye and Retention Chemicals The cooking of bagasse may be done in an alkaline medium to separate the components present in the bagasse. In the next stage of the washing process of the cooked bagasse, non-fibrous material like lignin, sugar, minerals may either be dissolved or separated as black liquor to obtain clean cellulose. The obtained cellulose may be sent to the bleaching process where bleaching chemicals are added to obtain the desired brightener pulp. In some embodiments the paper is bleached. In some embodiments the paper is unbleached. The weight of a base material and / or of a coated material may, for example, be: 5 <40 g / m2 40- 120 g / m2 120-200 g / m2 >200 g / m2 10 Weight = weight in grams of one square meter of paper or board (g / m2); also basis weight. Some embodiments, for example, provide a material having a weight in the range 35-80 15 g / m2, for example 35, 40, 50 or 60 g / m2. Examples of technical specifications are shown below in Table I. TICHHICAL SFEC1RCMONS K so fe:M i §■ $ 0 S 38 37 fem hfe W; 70S fejj SO 80 OS OS 8 a so S..4 IS 3: 3 3 CM O O 3883 fefe 4300- .safe femfey yofefe IW 300 as 38 28 ISO 07 S3 os 38 38 pHVsh® 0*75 O - ?S 88*75 ; Coatings might vary but the same purpose still applies. Alternative coatings are, for example, poly lactic acid (PLA - a biodegradable polymer derived from lactic acid), or 5 wax-based. Paper formed in accordance with the present invention may be provided as / on reels and sheets. 10 Different aspects and embodiments of the invention may be used separately or together. Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features of the dependent claims 15 may be combined with the features of the independent claims as appropriate, and in combination other than those explicitly set out in the claims. Each aspect can be carried out independently of the other aspects or in combination with one or more of the other aspects. The present invention will now be more particularly described, by way of example, with reference to the accompanying drawings. The example embodiment is described in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternative forms and should not be construed as limited to the examples set forth herein. There is no intent to limit to the particular form disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiment are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate. Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealised or overly formal sense unless expressly so defined herein. In the following description, all orientational terms, such as upper, lower, radially and axially, are used in relation to the drawings and should not be interpreted as limiting on the invention. Figure I shows a packaging material generally indicated 10. In this embodiment the product is used for Oil and Grease Resistance (OGR) applications. This is achieved by using a waterborne coating that has high-performance oil and grease resistance and has a good heat sealability. The material 10 includes a core formed as a laminar base material 20 which is coated on both sides with a PLA coating layer 30, 40. Figure 2 shows a packaging material generally indicated 110. In this embodiment the product is used for Water Barrier Resistance (WBR). This is achieved by using a waterborne coating 130, 140 that improves water vapour resistance and has a good heat sealability. The base material in some embodiments of the present invention may be a bagasse base. The dry bagasse may comprise: • 45% cellulose • 28% hemicellulose • 20% lignin • 5% sugar • I % of minerals . 2% ash. Some embodiments are formed as a bleached grade using a mix of bagasse fibres. Recycled fibres are used with good strength and brightness (for example for good printability). 5 Embodiments may have high burst factor (tear factor) strength. Some embodiments may be formed to have a smooth and / or bright surface. Some embodiments may be calendered. 10 Examples of Coatings - Table 2 Coating Material Recyclable Compostable Repulpable Printing Machine Notes X Water Based Poly Coating TRUE FALSE TRUE Gravure or rod coating equipment Liquid Barrier - Heat resistant Y Not Plastic Not PLA TRUE TRUE FALSE Water and grease proof barrier -coating can be used for food, flexible packaging and cups Z Water-based polymer emulsions or solid biowaxes TRUE TRUE TRUE Paper machine coaters and offline Repel water and water vapor, hot and cold liquids, and oils and greases. A Polybutylene Succinate TRUE TRUE TRUE Barrier Packaging -Coffee cups -Cutlery B VaporCoat / Water Based Coating TRUE FALSE TRUE Low Odour, Low MVTR, Water, and grease resistant coating / For food and non-food packaging, can replace PE, can be used on K C Mineral Enriched -Resin, mainly made from Calcium Carbonate TRUE FALSE TRUE Waterproof -Greaseproof -Heat-sealable Coating X is a water-based poly coating. When applied on a paper base it sustains the recyclability and repulpability but not the compostability. It has a liquid barrier, and is heat sealable 5 Coating Y is a coating that replaces PE and PLA. It may be used for different applications; it has a water and grease proof barrier and therefore can be used for food, flexible packaging and cups. It is recyclable, biodegradable and compostable (most probably repulpable too). 10 Coating Z is a coating that could either be water-based polymer emulsion or solid biowax. It repels water and water vapor for hot and cold liquids, and also is a barrier for oil and greases. It is recyclable, compostable, biodegradable and repulpable. 15 Coating A is Polybutylene Succinate made coating. It can be used as barrier for packaging, for cups and also in cutlery. It is compostable, recyclable and repulpable. Coating B is a recyclable and repulpable water-based coating. It is a moisture, water and oil and grease barrier. It can be used for food packaging as well as dry food packaging. 5 Coating C is a mineral enriched resin coating mainly made from Calcium Carbonate, it is recyclable and repulpable. Can be used for several applications: paper cups, food trays, folding cartons, take out boxes, labels, liners, corrugated packaging, flexible bags and more. 10 In some embodiments both sides of a paper base are coated. In some embodiments only one side of a paper base is coated. In some embodiments the coating applied to both sides is the same. In some embodiments a different coating is applied to each side of a base. 15 Further examples of coatings are shown in Table 3. Coating Company Coating Name Material Recyclable Compostable Repulpable Note BASF (RTM) Ecovio (RTM) PS 1606 Biopolymer -ecoflex and PLA TRUE FALSE TRUE Barrier against oil and grease, aroma, mineral oil, liquid COLOMBIER bespoke Not Plastic Not PLA TRUE FALSE TRUE Water and grease proof barrier -coating can be used for food, flexible packaging and cups SOLENIS bespoke Water Based TRUE FALSE TRUE (RTM) coating Michelman (RTM) MC 95 / Bespoke Water Based coating TRUE FALSE TRUE Water, and grease resistant coating Heat and cold glue sealable Smart Planet Technologies Earth Coating Mineral Enriched - Resin, mainly made from Calcium Carbonate TRUE TRUE TRUE Waterproof Greaseproof Heatsealable Munzing (RTM) Wukoseal 2800 waterborne dispersion for use as oil / grease and water proof coating applied on paper and cardboard. Lamination of paper / aluminium foil TRUE FALSE TRUE Waterproof, Greaseproof and Heat sealable Further information is available from the following web-sites. https: / / www.basf-coatings.com / gtobal / ecweb / en / 5 htfos: / / www.cotombier.corn / produm-2 / #s3 .............................. https: / / solenis.com / en / solutions / pulp-paper-solutions / barrier-coatings / 10 https: / / www.michelrnan.com / Michent-Coat / Michem(r,)-Coat-95 / httDs: / / www.smas"tplanettech.com / technologv ........>...................................... W- Although illustrative embodiments of the invention have been disclosed in detail 15 herein, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention.

Claims

I. A method to form bagasse-based food packaging material, the food packaging material comprising a paper core formed by: i) processing sugarcane to obtain bagasse base; ii) de-pithing the bagasse; ii) cooking the bagasse in an alkaline medium; iii) bleaching of pulp; iv) washing of pulp; v) pressing of pulp; vi) transferring white pulp to a paper machine to make paper in reel or sheet form having a weight of approximately 35, 40, 50 or 60 g / m2and having technical specifications substantially as defined in Table I; vii) calendaring the paper; and viii) applying a waterborne, waterproof coating of PLA on both sides of the paper core.

2. A method to form bagasse-based food packaging material, the food packaging material comprising a paper core formed by: i) processing sugarcane to obtain bagasse base; ii) de-pithing the bagasse; ii) cooking the bagasse in an alkaline medium; iii) bleaching of pulp; iv) washing of pulp; v) pressing of pulp; vi) transferring white pulp to a paper machine to make paper in reel or sheet form having a weight of approximately 35, 40, 50 or 60 g / m2and having technical specifications substantially as defined in Table I; vii) calendaring the paper; and viii) applying a waterborne, waterproof wax-based coating on both sides of the paper core.

3. A method as claimed in claim I or claim 2, with a coating selected from Table 3.

4. A method as claimed in any preceding claim, in which the paper core comprisesapproximately 75% bagasse and approximately 25% wood tree fibre.

5. A method as claimed in any preceding claim, having a dry bagasse base contentof approximately:• 45% - 55% cellulose• 20% - 28% hemicellulose• 20% lignin• 5% sugar• I % minerals. 2% ash6. A method as claimed in any preceding claim, having a dry bagasse base content of approximately:• 45% cellulose• 28% hemicellulose• 20% lignin• 5% sugar• I % of minerals. 2% ash.

7. A method as claimed in any preceding claim, comprising a waterborne coating that has oil and grease resistance and has a heat sealability.

8. A method as claimed in any preceding claim, in which the bagasse base further comprises sugar beet agricultural waste.

9. A method as claimed in any preceding claim, in which the fibre length ofbagasse material is in the range 1.2 -1.5 mm.

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