If you look at the bottom of most plastic bottles and many plastic products, you will see a number or numbers surrounded by arrows that form a triangle. These numbers were developed by the Society of the Plastics Industry or SPI, and they are part of a resin identification coding system and commonly known as resin codes. Basically, the purpose of the code is to identify the type of plastic that was used to create the plastic.
In many parts of the country, items with a number one or number two are the only types accepted for municipal recycling programs. The number one indicates items that are made from the polymer polyethylene terephthalate or PET which includes soft drink bottles and water bottles. Biaxially oriented PET film is known more commonly as Mylar, and this is used for thin, flexible food packaging and other products. Thermoforming is used to create these products, which begin, as a large sheet of thin plastic. Heat is applied, and the plastic is formed to a mold, then cooled and trimmed to create a finished product.
When the number on your plastic is a two, this is plastic that has been created with high-density polyethylene. Many products, including grocery bags, milk jugs and containers for food storage are made using this polymer, which is sometimes called HDPE plastic. This type of plastic is also used from some toy items, such as hula hoops, and even used in some reconstructive surgeries.
A wide variety of items are produced with polyvinyl chloride, which is identified using the number three. It's also more commonly just called PVC, and you can find PVC pipes in any hardware store. It is also used to make vinyl clothing and upholstery as well as shower curtains and even toys. The resin code of four, which is low-density polyethylene or LDPE, is used for a wide variety of items, including the plastic rings that hold together your cans of beer or soda. Because of its high resistance to many chemicals, it is also useful for making equipment for laboratories.
While it might not seem like diapers and carpet have much in common, both contain a bit of resin number five, which is polypropylene. This is a durable polymer which is also used to make bottle tops, such as flip tops on ketchup or salad dressing, as well as furniture. Because it is fairly heat resistant it can be used in laboratories, as well. Polystyrene is yet another type of polymer, and it is marked with resin code six and is often known by the brand name of Styrofoam. But generic versions of this polymer are used to create a variety of containers and cups, as well as packing peanuts that keep items safe in parcels during transit.
Strangely, there is no number eight, but there is a seven and a nine. Seven contains items that were created from an assortment of plastics, as well as nylon products and acrylic products. Nine is called ABS or acrylonitrile butadiene styrene, and it is very hard and durable and used to make Legos as well as musical instruments, pipes, golf club heads and much more.
In many parts of the country, items with a number one or number two are the only types accepted for municipal recycling programs. The number one indicates items that are made from the polymer polyethylene terephthalate or PET which includes soft drink bottles and water bottles. Biaxially oriented PET film is known more commonly as Mylar, and this is used for thin, flexible food packaging and other products. Thermoforming is used to create these products, which begin, as a large sheet of thin plastic. Heat is applied, and the plastic is formed to a mold, then cooled and trimmed to create a finished product.
When the number on your plastic is a two, this is plastic that has been created with high-density polyethylene. Many products, including grocery bags, milk jugs and containers for food storage are made using this polymer, which is sometimes called HDPE plastic. This type of plastic is also used from some toy items, such as hula hoops, and even used in some reconstructive surgeries.
A wide variety of items are produced with polyvinyl chloride, which is identified using the number three. It's also more commonly just called PVC, and you can find PVC pipes in any hardware store. It is also used to make vinyl clothing and upholstery as well as shower curtains and even toys. The resin code of four, which is low-density polyethylene or LDPE, is used for a wide variety of items, including the plastic rings that hold together your cans of beer or soda. Because of its high resistance to many chemicals, it is also useful for making equipment for laboratories.
While it might not seem like diapers and carpet have much in common, both contain a bit of resin number five, which is polypropylene. This is a durable polymer which is also used to make bottle tops, such as flip tops on ketchup or salad dressing, as well as furniture. Because it is fairly heat resistant it can be used in laboratories, as well. Polystyrene is yet another type of polymer, and it is marked with resin code six and is often known by the brand name of Styrofoam. But generic versions of this polymer are used to create a variety of containers and cups, as well as packing peanuts that keep items safe in parcels during transit.
Strangely, there is no number eight, but there is a seven and a nine. Seven contains items that were created from an assortment of plastics, as well as nylon products and acrylic products. Nine is called ABS or acrylonitrile butadiene styrene, and it is very hard and durable and used to make Legos as well as musical instruments, pipes, golf club heads and much more.
About the Author:
Lenna Stockwell enjoys writing about how stuff is made. For further details about retail product packaging or to find out more about food packaging design, please go to the Indepak site now.
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