7 Types of Plastic: The Different Materials and Grades

Take your nearest plastic product, the lunch box you brought from home, or your water bottle, your instant noodle cup. Study closely, you might find a number at its back or bottom.

You probably already know what it is. The number 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 has the biggest chance of damaging the environment?

Here are the 7 types of plastic that you need to know

1. PET or PETE or Polyester (Polyethylene Terephthalate)

Polyethylene (PE) Terephthalate or PET is also known as a wrinkle-free fiber. It' s different from the plastic bag we commonly see at the supermarket.

This type of plastic polymer is mostly used for food & drink packaging purposes, due to its strong ability to prevent oxygen from getting in & 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 programs, this type of plastic contains antimony trioxide—a matter that is considered as a carcinogen—capable of causing cancer in a living tissue.

2.HDPE (High-Density Polyethylene) Plastic Type

Quite unique compared to the other types, HDPE has long virtually unbranched polymer chains which makes them really dense & thus, stronger & thicker from PET.

HDPE is a plastic-type commonly used in a grocery bag, opaque milk, juice container, shampoo bottle, and medicine bottle.

Not only recyclable, but HDPE is also relatively more stable than PET. It is considered a safer option for food and drink use, although some studies have shown that it can leach estrogen-mimicking additive chemicals that could disrupt the human’s hormonal system when exposed to ultraviolet light.

3. PVC (Polyvinyl Chloride) Plastic Type

Polyvinyl Chloride is typically used in toys, blister wrap, cling wrap, detergent bottles, loose-leaf binders, blood bags, and medical tubing.

This plastic type used to be the second most widely used plastic resin in the world (after polyethylene), before the manufacture and disposal process of PVC has been declared as the cause of serious health risks and environmental pollution issues.

In the term of toxicity, PVC is considered the most hazardous plastic. The use of it may leach 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.

PVS is also rarely accepted by recycling programs. This is why PVC is better best to be avoided at all costs.

4. LDPE Plastic Type (Low-Density Polyethylene)

As said before, Polyethylenes are the most used family of plastics in the world. This type of plastic has the simplest plastic polymer chemical structure, making it very easy and very cheap to process.

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, newspapers, garbage), plastic wraps; coatings for paper milk cartons and hot & cold beverage cups; some squeezable bottles (honey, mustard), food storage containers, container lids. They are also used for wire and cable covering.

Although some studies have shown that LDPE could also cause unhealthy hormonal effects in humans, LDPE is considered a safer plastic option for food and drink use. Unfortunately, this type of plastic is quite difficult to be recycled.

5. Polypropylene Plastic Type (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 in thermal vests, and car parts, PP is also included in the disposable diaper and sanitary pad liners.

Same as LDPE, PP is considered a safer plastic option for food and drink use. It’s a good material for baby milk bottle, as long as made of food-grade plastic and identified as “BPA-free.”

Although it bears all those amazing qualities, PP isn’t entirely recyclable and could also cause asthma and hormone disruption in human.

6. PS (Polystyrene) Plastic Type

Polystyrene (PS) is the styrofoam we all commonly used for food containers, egg cartons, disposable cups and bowls, packaging, and also bike helmet.

When exposed to hot and oily food, PS could leach styrene is considered as brain and nervous system toxicant. It could also affect genes, the lungs, the liver, and the immune system. On top of all of those risks, PS has a low recycling rate.

7. Other Plastic Materials

Number seven is for all plastics other than those identified by numbers 1-6 and also plastics that may be layered or mixed with fifferent types of plastics, such as bioplastics.

Polycarbonate (PC) is the most common plastic in this category, isn’t used as much in recent years due to it being associated with bisphenol A (BPA).  PC is also known by various name: Lexan, Makrolon, and Makroclear.

Ironically, PC is typically used for baby bottles, sippy cups, water bottles, water gallons, metal food can liners,  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, and various behavioral changes.

It has also been linked to 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 with its very low recycle rate quality, PC is to be avoided at all costs.