Background/Problem Description::
Natural adhesives are often referred to as bio adhesives, made from organic sources such as vegetable, natural resins & gums, or animals. These include organic materials such as casein, blood, albumin, bone, fish, starch, resin, gum, asphalt, chitosan, and inorganic adhesives like sodium silicate. Their use, except for the inorganic adhesives, is mostly limited to paper, paperboard, foil, and light wood. These adhesives develop tack quickly but have low strength properties. Most are water-soluble and use water as a solvent.:
Natural adhesives are gaining popularity among users and manufacturers because of their non toxic, biodegradable and eco-friendly properties. Theses adhesives are typically free from harmful solvents and volatile organic compounds (VOCs) that can cause air pollution. Derived from renewable resources, natural adhesives are a more sustainable choice, advocating a circular economy and reducing carbon footprint, compared to synthetic adhesives made from petroleum byproducts. Natural adhesives are usually biodegradable, which means they break down naturally over a period of time, mitigating the environmental hazards created by the synthetic ones. These adhesives offer a high level of versatility, making them suitable for a wide range of applications, from woodworking and paper crafts to flooring and tiles. These adhesives are generally safer to use, as they contain, if any, very less amount of harsh chemicals.:
Natural resins have been used as adhesives. Shellac is used in bonding mica splittings to form micaboard and used in abrasives. Gum arabic is used in remoistenable adhesives. Copal gums are used in spirit-soluble lino cements.:
The trend of using disposable dining ware in outdoor and in-house functions is booming. Disposable dining plates and bowls are generally made of synthetic materials such as plastic or thermocol, which have excellent barrier properties but are not environment friendly. The disposable plates made up of plastics such as polythene, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, etc., pose health risks due to the release of toxic chemicals, such as bisphenol A, melamine, vinyl chloride, and phthalates. Plastic pollution, predominantly from disposable food packaging materials, has emerged as a global critical environmental challenge. Another class of disposable plates comes with semi-synthetic combinations like plastic laminated paper sheets or ACP (Aluminium coated plastic) laminated papers. The presence of plastic in such plates also makes them non-biodegradable. Natural dining ware made up of a single large tree leaf or several small leaves hand-stitched has been used in tropical and semitropical countries for ages. These are biodegradable and eco-friendly. Most plant leaves possess functional compounds that exhibit antimicrobial activity, and hence, they protect against food borne pathogens. Also, plant leaves contain polyphenols in large amounts, which act as antioxidants and restrict food spoilage by inhibiting the oxidation process. However, the plant leaf-based dining ware have shelf-life issues, are prone to wear and tear, and have a liquid food leakage problem. Paper without plastic laminations fails to deliver the required barrier properties for withstanding oils and liquid food and lacks mechanical strength.:
Modern disposable plates come with composite layers of paper and tree leaf bound together with suitable binder, mostly plastic sheets, to overcome the leakage and strength issues. The hot melt plastic used as a sandwich binder here still creates problems with degradation of such disposable plates. Hydrophilic natural gums as binders for such dining ware invite mould in humid conditions and lack moisture barrier properties. Hence, the need for eco-friendly adhesives with binding and moisture barrier properties like plastic is in high demand to address this issue.:
Technology Description:
A natural and eco-friendly adhesive has been developed as an alternative to plastic, with strong adhesion, waterproofing effect, and enough mechanical strength for leaf dining utensils. The adhesive is water resistant and plates developed using it can hold liquids in both hot and cold. The adhesive will replace the plastic binder in disposable dining ware, mitigating environmental concerns and associated health hazards