Adapted from an article by
Amanda Bahraini In Waste Management
7 Types of Plastic that You Need to Know
Plastic isn’t as simple as you may think. Some plastics are reusable; others produce hazardous material after several uses. Some are easily recyclable; others need more sophisticated handling in their recycling process. Take your nearest plastic product, maybe the lunch box you brought from home, your water bottle, your instant noodle cup. Study closely, and you might find a number at its back or bottom. This indicates the type of plastic used to make the product you are holding right now. But do you know exactly what number you should avoid and what number holds the biggest chance of damaging the environment?
Essential information (if you can bear reading it!):
Readily recyclable: Polyethylene Terephthalate (PET or PETE or Polyester)
PET is also known as a wrinkle-free fiber. It’s different from the plastic bag that we commonly see at the supermarket. PET is mostly used for food and drink packaging purposes due to its strong ability to prevent oxygen from getting in and spoiling the product inside. It also helps to keep the carbon dioxide in carbonated drinks from getting out.
Although PET is most likely to be picked up by recycling programmes, this type of plastic contains antimony trioxide—a compound that is considered as a carcinogen—capable of causing cancer in a living tissue. The longer a liquid is left in a PET container the greater the potential for the release of the antimony trioxide. Warm temperatures inside cars, garages, and enclosed storage could also increase the release of this hazardous substance. This should not give undue cause for alarm, but maybe worth keeping in mind next time you pick up a bottle of water that has been left in your car over several hot days! Also, PET is most unsuitable for microwaving.
Bottles made from polyethylene terephthalate (PET, sometimes PETE) can be recycled and used to manufacture new bottles and containers, thermoform packaging, strapping and are also used in fibre applications such as carpet and apparel.
Readily recyclable: High-Density Polyethylene (HDPE)
Quite special compared to the other types of plastic, HDPE has long virtually unbranched polymer chains which makes it really dense and thus stronger than PET. HDPE is commonly used as grocery bags (“for life”), opaque milk and juice containers, shampoo bottles and medicine bottles.
Not only recyclable, HDPE is more stable than PET in relative terms. It is considered as a safer option for food and drinks use, although some studies have shown that it can leach oestrogen-mimicking additive chemicals that, after exposure to ultraviolet light (i.e. the sun) could disrupt a human’s hormonal system.
HDPE can be recycled to manufacture e.g. pens and detergent bottles.
NOT recyclable: Polyvinyl Chloride (PVC)
PVC is typically used in toys, blister wrapping, cling film, detergent bottles, loose-leaf binders, blood bags and medical tubing. PVC or vinyl used to be the second most widely used plastic resin in the world (after polyethylene, commonly called polythene), before the manufacture and disposal process of PVC was declared as the cause of serious health risks and environmental pollution issues.
In terms of toxicity, PVC is considered to be the most hazardous plastic. Its potential leachates include a variety of toxic chemicals such as bisphenol A (BPA), phthalates, lead, dioxins, mercury, and cadmium. Several of the chemicals mentioned may cause cancer; it could also cause allergic symptoms in children and disrupt the human’s hormonal system. PVC is also rarely accepted by recycling programs and is best avoided at all cost.
Although PVC products may carry a 3 in a triangle of arrows, that 3 means “Non Recyclable Plastic”
Poor recyclability: Low-Density Polyethylene (LDPE)
Polyethylenes, or polythenes, are the most widely used family of plastics around the world. This type of plastic has the simplest plastic polymer chemical structure, making it very easy and very cheap to manufacture. LDPE polymers have significant chain branching including long side chains making them less dense and less crystalline (structurally ordered) and thus a generally thinner more flexible form of polyethylene.
LDPE is mostly used for bags (grocery, dry cleaning, bread, frozen food bags, magazine wraps, garbage bags), plastic wraps; coatings for paper milk cartons and hot & cold beverage cups; some squeezable bottles (honey, mustard), food storage containers, container lids. It is also used for wire and cable sheathing applications.
Although some studies have shown that LDPE could also cause unhealthy hormonal effects in humans, LDPE is considered as a safer plastic option for food and drink use.
Bin liners and similar low-hygiene flexible plastic wrap articles.
Medium recyclability: Polypropylene (PP)
Stiffer and more resistant to heat, PP is widely used for hot food containers. Its strength quality is somewhere between LDPE and HDPE. Besides thermal vests, and car parts, PP is also a component in disposable nappy/diaper and sanitary pad liners. Like LDPE, PP is considered a safer plastic option for food and drink use. However, PP isn’t extensively recyclable and could also cause asthma and hormone disruption in humans.
Polypropylene can be recycled into brooms, brushes, garden rakes and plastic trays.
NOT recyclable: Polystyrene (PS)
Polystyrene, in its expanded form made by blowing gas into the liquid polymer, is the Styrofoam we all commonly used for food containers, egg cartons, disposable cups and bowls, packaging, and also bike helmets. The non-expanded resin is used for CD cases, plastic cutlery ad similar brittle articles. When exposed to hot and oily food, expanded PS could leach styrene, a substance considered to be a toxicant affecting the brain and nervous system. It could also affect a person’s genetic health, lungs, liver, and immune system. PS has a low recycling rate.
Although PS products may carry a 6 in a triangle of arrows, that 6 means “Non Recyclable Plastic”
NOT recyclable: Other
Number 7 is for all plastics other than those identified by numbers 1-6 and also plastics that may be laminated or mixed with other types of plastics, such as bioplastics. Polycarbonate (PC) is the most common plastic in this category. Its use is on the decline due to it being associated with bisphenol A (BPA). PC is known by various names: Lexan, Makrolon, and Makroclear. Ironically, PC is typically used for baby bottles, sippy cups, water bottles, water gallons and as a liner in metal food cans, ketchup containers and dental sealants. Due to its toxicity, several countries have banned the use of PC for baby bottles and infant formula packaging.
The BPA contained inside PC has been linked to numerous health problems including chromosome damage in female ovaries, decreased sperm production in males, early onset of puberty, various behavioural changes, altered immune function, sex reversal in frogs, impaired brain and neurological functions, cardiovascular system damage, adult-onset (Type II) diabetes, obesity, resistance to chemotherapy, increased risk of breast cancer, prostate cancer, infertility, and metabolic disorders.
Added to its very low recycle rate, PC is to be avoided at all cost.
Other plastics are not recyclable in normal collections. This categorises all other plastics including bioplastics, composite plastics (like crisp wrappers), plastic coated wrapping paper and polycarbonate (which contains BPA).
3 Important Things!
Memorizing all of those 7 different types of plastic could be overwhelming, so here are some key points worth remembering:
- Every single category of plastic could leach hazardous materials if exposed e.g. to extreme heat.
- Three types of plastic that are considered as safer options are Polyethylene Terephthalate (1 – PET), High-Density Polyethylene (2 – HDPE), and Polypropylene
(5 – PP).
- With research into the most appropriate technologies for recycling each of these plastic resins still ongoing, the two types of plastic that are currently mostly likely to be picked up by recycling programmes are Polyethylene Terephthalate (1-PET) and High-Density Polyethylene (2-HDPE).
We hope you now know what type of plastic you want to use as your food and drink containers and what plastic you may want to avoid due to its low recycle rate quality. Don’t forget to separate your waste items responsibly.