How do you identify hard plastic?

Hard plastic, scientifically identified as High-Density Polyethylene (HDPE), is probably the most common type of plastic we see in our household. It is used for shampoo bottles, grocery bags, and milk containers, among others. Though versatile and flexible, hard plastic is one of the most complicated types of plastic.

Identifying hard plastic

Identifying hard plastic is crucial for us to know how we can recycle plastic materials in case we cannot completely stop using them. There are 7 different types of plastic, most of which we could do without so we do not contribute to plastic pollution.

What sets hard plastic apart from the others is its density. Because it is made of HDPE, it is not as lightweight as other plastic types. This quality also makes it more versatile to be utilized for various industries, including food packaging. 

Hard plastic is also stiffer and more rigid. Its versatility stems from its natural malleability, making it easy to form into different containers. This type of plastic is also identified to be generally food-safe. 

Not only is hard plastic recyclable, it could also be repurposed to be made into plastic crates and fences after serving its purpose as milk jugs, trash bags, and toys. 

Where to spot hard plastic

Considered to be the safest bet when it comes to containing food and beverage, hard plastic is the most used type of plastic in the food industry. Roaming around the supermarket, you can see hard plastic in every aisle.

Used for containing milk and juices, hard plastic is the material used in gallons and grocery plastic bags. Its high density equates to a high level of durability, making it ideal to be made as medicine bottles as well. 

Apart from food and medicine, it is also utilized to contain shampoo, liquid soap, detergent, bleach, and other cleaning agents. 

However, there is more to hard plastic than the supermarket and household. It is also used in plastic surgery, specifically for face reconstruction. This type of plastic has also been found to be an active ingredient in wood plastic composites, snowboards, and as a 3D printing filament.

Properties of hard plastic

To be more technical, what sets hard plastic apart from other types of plastic is its long virtually unbranched polymer chains. These chains contribute to its high density and strength. Hard plastic also has a higher melting point and impact resistance, which makes it perfect to be made as cutting boards and piping.

Initially invented to be used for pipes and sewers, hard plastic is now known for its versatility to be used in various industries. Because it does not break even under extreme weather conditions, it remains to be the most recycled type of plastic.

Made of petroleum, hard plastic could be treated to resist corrosion. Instead of being thrown after use, this type of plastic can be repurposed. It is most commonly turned into plastic lumber, crates, and geomembrane. 

Common questions about identifying hard plastic

👉 Can you weld hard plastic?

Yes. There is such a thing called hard plastic welding. The idea is to apply heat to the edges of the broken plastic until you can test its malleability and see if you can join the pieces together while they are melting. Once they are liquid enough, you can then blend them and re-create it back to its original form.

👉 What is the strongest type of plastic?

Polycarbonate and acrylic plastics are the strongest types. These are clear and stiff plastic sheets strong enough to be used in architectural projects. Their high transparency and mechanical properties set them apart from weaker and lighter plastic types. 

👉 What is the hardest clear plastic?

Also the strongest, polycarbonate is the hardest clear plastic. Polycarbonates are a group of thermoplastics that are highly resistant to both heat and impact. Quite comparable to glass, polycarbonate plastic can also transmit light and is naturally transparent.
Hard plastic is one of the most used plastic types. We use it every day at home, and practically makes up a huge chunk of the trash we produce. Because it is widely used, it is important that we identify them from the others to be able to recycle and reuse them if possible. 
Knowing which is which will make it easier for us to be more mindful of how we dispose of our plastic. Proper knowledge could also be a way for us to reuse and recycle plastic instead of just throwing them out and adding to the world’s current problem on plastic pollution.

How do you identify hard plastic?