Plastic packaging bags, or poly bags, have two rectangular plastic sheets fused on three sides, with one side open. They come in all shapes, sizes and varieties, as jumbo bin and drum liners, garbage bags, kitchen tidy bags, heavy duty bags, carton liners, bubble bags, freezer bags, sandwich bags, sweets bags, garment covers, gift bags, pallet bags, bags on rolls for easy tear-off, drawstring bags, gusseted bags (a fitted bottom and expandable sides), zip lock bags, shrink film bags, and stretch film bags.
These plastic packaging bags are usually made of high density polyethylene (HDPE) because of its exceptional barrier against moisture and because of its chemical resistance. When HDPE bags are used for food packaging, they are restricted to foods that do not need an oxygen or carbon dioxide barrier. As a film plastic, HDPE is ideal for snack-food packing and cereal box lining, and for blow-moulded bottles, beverage bottles, margarine tubs, coverings for other delicatessen foods, and bread trays. HDPE’s chemical resistance makes it ideal for plastic packaging household detergents.
Plastic packaging bags keep food fresh for longer, thereby reducing food wastage. In addition, plastic bags are shipped more efficiently than paper bags. It takes one truck to carry plastic bags compared to seven trucks for the same quantity of paper bags.
Plastics today are lighter. Before 1977, the two-litre plastic drink bottle weighed 68 grams. Today, it weighs 47 grams. This is a 31 per cent reduction per bottle, which in 2006 saved more than 82 million kilograms of packaging for two-litre bottles alone.
Plastics manufacturers are keen to do their bit in protecting the environment. They point out that less material goes into making custom plastic packaging, which in turn results in less waste and helps save the Earth’s natural resources. In addition, according to the Film and Bag Federation based in Washington D.C., U.S.A., compared to paper grocery bags, plastic bags consume 40 per cent less energy, generate 80 per cent less solid waste, produce 70 per cent fewer atmospheric emissions, and release up to 94 per cent fewer waterborne wastes. Conserving resources in this way also saves energy. Plastic packaging bags manufacturers generate less greenhouse gas and use less fresh water than paper bag manufacturers.
Manufacturers are also keen to point out that plastic packaging bags make up less than 1 per cent of the litter on our streets. The majority of litter consists of food containers, bottles and cans. Plastic bags that end up in landfill take up very little space. What takes up the most space are paper and wood-based materials, and foodstuffs, which contribute to greenhouse emissions and groundwater pollution, while plastic does not.
Plastic bags are re-used time and again. One source estimates that four out of five people will re-use plastic bags in the household. Some uses include rubbish bin liners, cat litter liners, soiled nappy containers, dog pooh retrievers, doggie bags in restaurants, shoe and clothes storage, packing material, and much more.