Anonymous asked in EnvironmentGreen Living · 1 decade ago

how are plastic bags made?

i have a report to do and its due soon but i need to know how are plastic bags made? wat are they made of and other things about plastic bags so please help!

2 Answers

  • 1 decade ago
    Favorite Answer

    Making a plastic bag is a pretty simple but at the same time complex event.

    Plastic resin pellets, which are available in different grades, are sucked from a storage bin and placed into a hopper. Then the pellets are ground up very finely and then melted, and then they are blown into a "bubble" through a process called extrusion.

    The machine that does this is called an extruder. Bubbles are made into varying widths. The bubble is drawn upwards and cooled at the same time. It is then folded and put onto a core to make a roll of plastic film. The roll of film is then placed onto a finishing machine where it may be cut down into different widths, or maybe a zipper seal is added or formed.

    Finishing: mold in a lock strip at the top on each half.

    then you fold it in half and bond the edges on two sides, that is the makings of most sandwich bags or freezer bags.

    Garbage bags are taking a sheet of plastic and vaccuumed into a tube. this gives you the shape, the tubes are changed to get the sizes of bags. The plastic is changed to get the mil thickness for heavly duty bags.


    Industrial manufacturing processes are fascinating to watch and few people know how common, everyday items are produced.

    Plastic bags start out life as large, thin rolls of plastic, often produced by the bag manufacturers from plastic pellets. The plastic can be produced in different colours by adding coloured pellets to the semi-transparent raw plastic. The roll of plastic is unwound and fed into the machine that produces the bags or the plastic film is extruded at the beginning of the line.

    The bags are printed using several rollers in sequence, each printing one colour at a time. A four-colour CMYK printing process (cyan, magenta, yellow, and black) is usually used.

    The film is then folded over on itself and heat-sealed along the side seam. Heavier gauge bags may be made from two rolls of plastic, brought together and joined at both sides. This forms a flattened tube of plastic. Handles may be added at this stage by a stamping / heat bonding process or molded directly into the bag. The bags are then formed by heat-sealing the bottom and cutting them to shape and size. Some heavy-weight bags have plastic handles added after the bags are made. Waste plastic from cuttings is recycled into new bags.


    See for more info:

    Pictures of Plastic Bag factories:

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  • Anonymous
    5 years ago

    confusing situation. lookup over google or bing. that will help!

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