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 some cities, recycling programs require that items must have a number one or a number two on the product in order for it to be eligible for recycling. Some cities, such as Los Angeles, will accept many other types of plastic, but many are not able to process anything but a one or two. The one is an indicator that the plastic was created using polyethylene terephthalate, which is commonly known as PET or PETE. Most plastic water and soft drink containers are made using this material, and one form of PET is used to make a thin plastic film often called Mylar. These PET products are created using a process known as thermoforming. As the name suggests, heat is used to warm plastic sheets to a malleable temperature, and it is then formed into shape using a special mold.
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.
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 some cities, recycling programs require that items must have a number one or a number two on the product in order for it to be eligible for recycling. Some cities, such as Los Angeles, will accept many other types of plastic, but many are not able to process anything but a one or two. The one is an indicator that the plastic was created using polyethylene terephthalate, which is commonly known as PET or PETE. Most plastic water and soft drink containers are made using this material, and one form of PET is used to make a thin plastic film often called Mylar. These PET products are created using a process known as thermoforming. As the name suggests, heat is used to warm plastic sheets to a malleable temperature, and it is then formed into shape using a special mold.
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.
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 likes writing about how stuff is made. For additional information about plastic thermoforming or to find out more about custom plastic packaging, please visit the Indepak website today.
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