How Are Plastic Trash Bags Made?
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Plastic Trash Bags: Ethane
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Plastic trash bags are a convenience most of us take for granted. Trash bags store our everyday household waste and also other trash forms including biohazardous waste found in hospitals and natural waste, such as fallen leaves. Plastic trash bags come from the earth and are eventually returned to the earth. The first ingredient that is needed in the process of making plastic trash bags is ethane. Ethane is a natural gas found in the ground, along with oil.
Before plastic trash bags can be made, a drilling process takes place to find an oil or a gas field's existence. After the field is found, a well is made to recover the oil and natural gas found. Many natural gases may be found, including methane, ethane, carbon dioxide and oxygen. Since the gas and oil do not separate on their own, they are put into a thermal flash column which separates the natural gas from the oil. Once all of the natural gases are recovered from the oil they are sent to a natural gas plant to be separated further. At the gas plant, the natural gases get separated into ethane, propane and butane by a distillation process. Ethane, one of the natural gases, then becomes the first ingredient in making plastic trash bags.
Plastic Trash Bag: Ethylene and Polyethylene
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After ethane is removed from the other natural gases, it then gets put into a thermal cracker, where it gets converted to ethylene. Thermal cracking is a method of using absolute pressures to produce a reaction called homolytic fissure which then produces alkenes. Alkenes are the basis for polymers, which is essentially what plastic trash bags are made from. Once ethylene is formed from the ethane by the thermal cracking, it travels to a reactor where it is turned into polyethylene polymers. Polyethylene polymers formed as resin pellets or beads when they go to a plastic trash bag manufacturer, but are actually large molecules made up of covalent chemical bonds.
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Polyethylene Polymers to Plastic Trash Bags
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The small resin pellets are converted by a process called extrusion to be turned into a pliable plastic. Resin pellets get put into a machine that heats them to a temperature of 200 degrees Centigrade and they become molten. Manufacturing companies then add agents to give the plastic color and to make it pliable. After the plastic polyethylene is formed, it is blown into a long tube which creates the bag shape. This shape is left to cool before it is collapsed to be cut and sealed. The bags will get cut to individual sizes and are heat sealed on one side, turning it into the plastic trash bag we all use in our homes. Many of these will be made at the same time by a machine that will roll or box the trash bags to complete the process.
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