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.
If you see a number two on your product, this is a resin code that identifies the polymer HDPE or high-density polyethylene. Everything from grocery bags to hula hoops to milk jugs is created with this HDPE plastic. Even plastic surgeons sometimes use this plastic as part of surgeries for facial reconstruction. Again, this type of plastic is one of the two most common types and one of the two most often accepted by recycling centers around the country, although you typically don't pay a deposit nor can you turn in these items and get your deposit back, as you can with water bottles and soft drink bottles.
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.
Polypropylene is a tough and highly resistant polymer, and this strength makes it appealing for use in a variety of products that come into contact with chemical solvents or acids. But this resin, designated with a 5, also is used to create diapers because unlike most plastics, it absorbs liquid rather than repelling it. If you have heard of Styrofoam, then you know a bit about the number six type of plastic. Styrofoam is a brand name for plastics that are made from polystyrene foam, and we see these every day in the form of cups and coolers and food containers.
The category identified with a seven is actual a mix of different kinds of plastics, such as acrylics and also nylons and items made with several kinds of plastic. There is no eight, but there is a nine, and it identifies a resin known as ABS or acrylonitrile butadiene styrene. If you have children who love to play with Legos, then you have come into contact with ABS.
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.
If you see a number two on your product, this is a resin code that identifies the polymer HDPE or high-density polyethylene. Everything from grocery bags to hula hoops to milk jugs is created with this HDPE plastic. Even plastic surgeons sometimes use this plastic as part of surgeries for facial reconstruction. Again, this type of plastic is one of the two most common types and one of the two most often accepted by recycling centers around the country, although you typically don't pay a deposit nor can you turn in these items and get your deposit back, as you can with water bottles and soft drink bottles.
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.
Polypropylene is a tough and highly resistant polymer, and this strength makes it appealing for use in a variety of products that come into contact with chemical solvents or acids. But this resin, designated with a 5, also is used to create diapers because unlike most plastics, it absorbs liquid rather than repelling it. If you have heard of Styrofoam, then you know a bit about the number six type of plastic. Styrofoam is a brand name for plastics that are made from polystyrene foam, and we see these every day in the form of cups and coolers and food containers.
The category identified with a seven is actual a mix of different kinds of plastics, such as acrylics and also nylons and items made with several kinds of plastic. There is no eight, but there is a nine, and it identifies a resin known as ABS or acrylonitrile butadiene styrene. If you have children who love to play with Legos, then you have come into contact with ABS.
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 visit the Indepak site today.
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