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.
The number three is used as a resin code to identify products made from polyvinyl chloride, which is commonly known as PVC. PVC is often used to create pipes and used in construction, but this plastic also is used to make plastic bottles that hold cleaners or other non-edible products and even used to create many toys. LDPE or low-density polyethylene is identified using a number four, and this plastic is often used in science labs because it is not affected by liquids that are acids, alcohols or bases. In addition, every time you buy a six-pack of beer or soft drinks, those flexible plastic rings are made from LDPE.
Polypropylene is designated with a five as its resin code, and this type of plastic can be used to produce a myriad of items. This is a very tough polymer and resists many chemicals. Furniture and carpets often contain polypropylene, and many ropes use this plastic as well. It is also used to create diapers and other types of sanitary products because it can absorb water. Number six plastics are made from polystyrene. Items made from this plastic include those little packing peanuts we put in shipping boxes as well as containers and cups. Styrofoam is a branded name for a type of polystyrene foam.
A seven is a number used for a miscellaneous category that includes items with a variety of different plastics in them, as well as plastics such as nylon and acrylic. There is no eight yet designated, but the number nine is used to identify products made from acrylonitrile butadiene styrene, also known as ABS. This type of thermoplastic is used to make a variety of interesting products, most notably Lego bricks.
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.
The number three is used as a resin code to identify products made from polyvinyl chloride, which is commonly known as PVC. PVC is often used to create pipes and used in construction, but this plastic also is used to make plastic bottles that hold cleaners or other non-edible products and even used to create many toys. LDPE or low-density polyethylene is identified using a number four, and this plastic is often used in science labs because it is not affected by liquids that are acids, alcohols or bases. In addition, every time you buy a six-pack of beer or soft drinks, those flexible plastic rings are made from LDPE.
Polypropylene is designated with a five as its resin code, and this type of plastic can be used to produce a myriad of items. This is a very tough polymer and resists many chemicals. Furniture and carpets often contain polypropylene, and many ropes use this plastic as well. It is also used to create diapers and other types of sanitary products because it can absorb water. Number six plastics are made from polystyrene. Items made from this plastic include those little packing peanuts we put in shipping boxes as well as containers and cups. Styrofoam is a branded name for a type of polystyrene foam.
A seven is a number used for a miscellaneous category that includes items with a variety of different plastics in them, as well as plastics such as nylon and acrylic. There is no eight yet designated, but the number nine is used to identify products made from acrylonitrile butadiene styrene, also known as ABS. This type of thermoplastic is used to make a variety of interesting products, most notably Lego bricks.
About the Author:
Lenna Stockwell enjoys blogging 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 now.
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