Plastic food containers are invaluable in the food production industry. They can be non-porous, easily cleaned and sealable, which helps keep food fresh and free from contaminants.
Since many raw plastic materials can be engineered or processed to be resistant to variable temperatures, food containers can be designed to resist cold or heat, which allows for the continued integrity of the container and helps increase the longevity of its contents. Food is transported in a wide variety of plastic containers.
Large bulk foods or liquids are often transported in sealed, High-Density Polyethylene (HDPE) drums or tubs, while smaller portions of condiments and soft drinks are sealed in polyethylene teraphthalate (PET). Many plastic food containers can be reused multiple times. Plastic tubs, bottles and jars are usually blow molded, a molding process similar to glass blowing, while larger and higher density containers are often injection molded.
Blow molding is one of the processes used to convert raw plastic material into a usable product. Blow molding is different from injection molding in process and in terms of the typical shape of a finished, blow molded product. Blow molding and injection molding processes are similar to a certain point; they both begin with a collection of raw plastic material, or stock, that is directed through a hopper and into a conveyance channel.
Inside the conveyance channel is a large screw that pressurizes and forces the stock past heating elements until the stock becomes molten. At the end of the conveyance channel is the mold recess. It is at this point where blow molds and injection molds are different. A blow mold is a cavity into which molten plastic is forced. The molten plastic takes the shape of the mold, and then pressurized air is blown into the mold, forcing the inside of the shape to become hollow. The newly molded plastic then cools and hardens under carefully controlled temperature conditions. After it emerges from the mold, it is cleansed of imperfections (if present) and then shipped to the customer or sent for additional processing.