Plastic is everywhere. We live among billions of it everyday and the number's always increase because they take a very long time to decompose (50-100 years).
But not all plastics are similar. And not all of us understand about this differece. Whereas to figure it out, we can be more aware of health and our bodies. We can determine which ones are safe for food or not, or which can be recycled or not. And for this reason, we need to know this 7 code of plastic by SPI (Society of the Plastic Industry).
#1: POLYETHYLENE TEREPHTHALATE (PET OR PETE)
Sample : Water bottles, cooking oil bottles, peanut butter jars, etc.
Strength : Recyclable, and safe (for food and beverage) *but should not be re-used or re-fill due to the risk of growing bacteria.
Weakness : Will increase the toxics over the EU limit, like phthalates and antimony, if stored in high temperature (up to 140 degrees Fahrenheit) or stored in room temperature for a too long time. Usually thin, because it is single-use purpose.
#2: HIGH DENSITY POLYETHYLENE (HDPE)
Sample : Detergent bottles, yoghurt tubs, milk jugs, bottle caps, backpack frames, hard hats, hula hoops, containers for milk, motor oil, shampoos and conditioners, soap bottles, detergents, and bleaches.
It's stiffer, "milkier," and non-transclucent plastic than PET (#1) plastic.
Strength : Dishwasher-safe and able to withstand temperatures from -148 to 176° F (-100 to 80° C), it's ideal for beverage and food storage containers. They are commonly recycled. It is considered safe and has low risk of leaching.
Weakness : HDPE resists UV penetration, which can damage and discolor the plastic.
#3: POLYVINYL CHLORIDE (PVC)
Sample : Plastic pipes, food wraps, outdoor furniture, flooring, siding, mobile home skirting, and other industrial-grade items.
Strength : Tough in terms of strength.
Weakness : Contains softening chemicals called phthalates that interfere with hormonal development. It is not considered safe to cook food near it. PVC is not often recycled.
#4: LOW DENSITY POLYETHYLENE (LDPE)
Sample : Plastic cling wrap, sandwich bags, squeezable bottles, and plastic grocery bags, plastic film. Recycled LDPE is used to make garbage cans, lumber, furniture, and many other products seen in and around the house.
Strength : It tends to be both durable and flexible. It also is not known to release harmful chemicals into objects in contact with it, making it a safe choice for food storage. Capable of being recycled in new products.
Weakness : Usually thin and easy to be torn. While considered safe, it is unfortunately not often accepted by curbside recycling programs.
#5: POLYPROPYLENE (PP)
Sample : Food containers, drinking straws, plastic diapers, tupperware, margarine containers, yogurt boxes, syrup bottles, prescription bottles, some stadium cups, ice scrapers, rakes, battery cables, and similar items that need to be durable.
Strength : Can usually withstand higher temperatures than other plastics. BPA-free, durable. good chemical resistance, good fatigue resistance. It has better temperature resistance than HDPE but lower density than HDPE.
Weakness : PP can be recycled but is not accepted for recycling as commonly as PETE or HDPE. Oxidative degradation is accelerated by contact with certain materials, e.g. copper. High mould shrinkage and thermal expansion, high creep, and poor U.V. resistance.
#6: POLYSTYRENE (PS)
Sample : plastic food boxes, plastic cutlery, packing foam, packing peanuts, cups, plastic tableware, meat trays, to-go "clam shell" containers.
Is most commonly known as styrofoam.
Strength : Lightweight and suitable for securing a product in the packaging of shock.
Weakness : Can be recycled, but not efficiently; recycling it takes a lot of energy, which means that few places accept it. Identifies numerous environmental impacts of polystrene, such as urban litter, marine debris, wildlife detriments when ingested and many more. Polystyrene food containers leach the toxin Styrene when they come into contact with warm foods or drinks, alcohol, oils and acidic foods—causing human contamination and posing a potential healthy risk to people who come into contact with it. Try to avoid them as much as you can.
#7: OTHER
Sample : Baby bottles, large water bottles (multiple-gallon capacity), compact discs, medical storage containers, certain kinds of food containers and tupperware
Is used to designate miscellaneous types of plastic that are not defined by the other six codes. Polycarbonate and polylactide are included in this category. Mother Earth News and numerous other credited sources are quick to point of that polycarbonate plastics and epoxy resins are produced using BPA. So, it is not recommended for food storage. But not all "other" plastic is polycarbonate, however. Plastics labeled #7 can also be a combination of several safe plastics. Individual research should be done when making decisions about #7 plastics.
Weakness : Difficult to recycle.
SOURCE :
https://www.qualitylogoproducts.com/lib/different-types-of-plastic.htm
http://www.reuseit.com/product-materials/learn-more-the-7-most-common-plastics-and-how-they-are-typically-used.htm
http://nontoxicrevolution.org/plasticsucks/the-7-types-of-plastic-what-they-mean-to-your-health/#.VlRRL3YrLDc