The types of plastic, the logos

What are the types of plastic, how to distinguish them, and where to find the logos. 

Historical Overview

The plastic was  first introduced to the public in 1862 by an English scientist Alexander Parkes. The brand was called “Parkesine”, but first, it wasn’t completely made of synthetic materials and was an alternative to ivory and the horns. Even though this material was a novelty, it didn’t achieve much commercial success. 

The plastic we use today, was invented by a German scientist Herman Staudinger in 1920. He discovered the polymers [i] and their various manifestations, for which he was awarded the Nobel prize in 1953. Over time, the polymer mixtures increased, becoming separate types of plastic, and since throwing the plastic to the landfill or burning it is not a solution (it doesn’t burn completely, and while burning, chemicals are emitted to the air), it became necessary to sort and recycle them. The Society of the Plastics Industry (SPI) (currently Plastics Industry Association) brought up a classification system for plastic in 1988: giving a chance to the consumers and the recyclers to differentiate between types of plastic. Producers put the SPI code or number on each plastic product, usually at the bottom.  

The types of plastic, their properties, logos, and everyday use

Let’s get acquainted with  the types of plastic, their properties, and plastic items used in our daily lives below.

1. Polyethylene terephthalate (PET) is marked with  number 1. Sometimes it absorbs the good or bad smell or the taste of the food or drink that it contains.  Containers or items made of this kind of plastic, are usually recycled.  Polyethylene terephthalate or PET, as it’s known in international terminology, is used in  the manufacture of various household items (such as drinks, medicine bottles,  ropes clothing and carpet fibers). 

2. The products made of high-density polyethylene (HDP) are marked with number 2. They are usually very safe. No case of emission of chemicals in food or beverage contained in them has been reported yet. The goods and containers made of high-density polyethylene or HDP are usually recyclable. Dairy containers, car oil containers, liquid soap and shampoo bottles, detergent and bleach containers are made of high-density polyethylene. It’s not safe to reuse the containers made of high-density polyethylene for food if it wasn’t intended for food from the beginning.

3. Polyvinyl chloride (PC) is marked with number 3 and sometimes is recycled. It is used in the production of all types of pipes and tiles, as well as plumbing pipes. 

4. Low-density polyethylene (LDP) is marked with number 4 and sometimes is recycled too. It is both resistant and flexible. Sticky food packagings, compressible bottles, and grocery bags are made of this.

5. Polypropylene (PP) is marked with number 5 and is rarely recycled. PP is hard and is usually able to withstand high temperatures. Kitchen utensils, yogurt containers, etc. are made of this. Plastic bottle caps also are often made of polypropylene. 

6. Polystyrene (PS) is marked with number 6 and is usually difficult to process. Food plastic soft containers, plastic tableware, etc. are made of it.

7. Number 7 (OTHER) is used for other types of plastic that don’t belong to the six subgroups mentioned above. Polycarbonate and polylactide belong to his group. This kind of plastic is difficult to recycle. Polycarbonate (PC) is usually used to produce discs, bottles for kids and items like this. 

In the conditions of the increasing quantity of trash and the continuous production of plastic, it is extremely important to know how to sort and recycle the trash.

Author: Marine Ohanjanyan © All rights reserved 

Translator: Argishti Yeghyan