Blow moulding is the process in which hollow, plastic containers are made. Air is blown into moulds to form items such as thermoplastic bottles, tubing and milk jugs. While blow moulding allows companies to manufacture high volumes of plastic containers, which are significantly cheaper than glass, there are a few disadvantages to the process. Some disadvantages include environmental hazards and a significant dependence on petroleum.
Plastic products made by the process of blow moulding aren't biodegradable, which presents an obvious environmental hazard, especially when empty containers find their way to landfills. When disposed of in landfills, plastic products are buried and remain in the earth forever. Their oil-based material then becomes part of the soil and runs the risk of threatening plant life, animals and groundwater.
Dependence on Petroleum
Aside from the gasoline industry, plastic manufacturers depend on millions of gallons of petroleum in their quest to produce blow-moulded products. Because oil is the most important agent in thermoplastics and blow moulding is becoming more streamlined and automated, the process plays an ongoing threat on a diminishing world oil supply.
Process and Material Limitations
Although blow moulding has been automated and can produce mass quantities of products, the process is largely limited to hollow forms. These forms are delicate and contain various thicknesses which must be precise, which often results in wasted material in the process of arriving at containers with proper dimensions and specifications. In some cases, thermoplastic is stretched to save on material, which can lead to substandard containers.