Types of Plastic

Plastic has emerged as one of the most commonly known materials across the world. It is used for making various products, ranging from toys to spaceships. The versatility of plastic is due to its physical properties like water resistance, relatively low cost and comparatively easy methods of manufacturing. It has replaced most of the traditional materials like wood, leather and glass. We all are familiar with plastic and use it in various forms in our day-to-day life. But, most of us may be unaware of the different types of plastic.

Classification of Plastic

There are many different criteria to classify plastic. As per the chemical structure, plastic is classified into various types; acrylic, polyester, silicone, polyurethane, and halogenated plastics. If classified on the basis of properties, which affect the product design, it can be categorized into; thermoplastic, thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastic can also be classified on the basis of method of production or physical properties. In short, there are various criteria for classifying plastic and it depends on the ultimate use. However, for a common man, most of these classifications are irrelevant.

Types of Plastic and Plastic Recycling

Plastic is a material, which degrades very slowly. It is said that, it takes around 100 to 500 years for discarded plastic to get degraded naturally. This revelation led to the concept of plastic recycling, which was promoted by almost all nations. However, this method confronted various hurdles and one among them was the different types of plastic that required different methods of recycling. There was no universal standards to classify plastic, which is used in various products. It was in 1988, the SPI (The Society of the Plastics Industry) designed the symbol code for plastic classification. The symbol code consists of a triangle of arrows, inside which there are numbers ranging from 1 to 7. Most of us are familiar with this symbol embossed on plastic items like pet bottles, yogurt cups, etc. This system of classifying plastic is considered to be a uniform coding system, which helps both consumers and recyclers to differentiate the various kinds of plastic. Apart from that, it gives a clear idea about which plastic is used for manufacturing that product.

Now, we know that plastic is classified through a number coding system which makes it easier to sort out different plastic items for recycling. The following are the different types of plastic, as per this coding system.

• The coding symbols start with number 1 (i.e, a triangle of arrows with number 1 inside it). This plastic is polyethylene terephthalate (PETE) and the easiest one to recycle. Pet bottles, medicine containers and water bottles are made of this plastic, which can be easily recycled to fiberfill for winter coats, sleeping bags and life jackets and can also be used in making bean bags and furniture.
• Those plastic items coded with number 2 are made up of a high density polyethylene (HDPE). This plastic is mainly found to be used to make detergent and shampoo bottles and milk jugs. This type of plastic is recycled to make rope, pipes and toys.
• Number three is assigned for those plastics, which are made of polyvinyl chloride (PVC). It is often found to used in the manufacture of shower curtains, window and door frames, plastic pipes, automotive parts, etc.
• Number 4 goes to those plastic items, that are made of low-density polyethylene (LDPE). This is found in sandwich bags, wrapping films, dry cleaning bags and trash can liners.
• Plastic items made of polypropylene (PP) are given the number 5. This plastic is used to make Tupperware, margarine tubs, microwaveable bowls and bottle caps.
• The next one is number 6, which is used to denote plastic made of polystyrene (PS) and is commonly known as Styrofoam. This plastic is mainly used in making coffee cups, meat trays, peanut packages and plastic tableware. This plastic can be recycled to make a rigid foam insulation and many other items.
• Number 7 is assigned to those plastics which do not fall under the categories of 1 to 7. These are not usually collected for recycling, as it is considered to be the most difficult category for recycling.

So, these are the different types of plastic, which are classified according to the use and chances of reprocessing. Among them, the number 1, 2 and 6 are commonly collected for recycling, but, 3, 4, 5 are not recycled on a regular manner. Plastic items without numbers too are not fit for recycling. So, you can reduce the use of plastic or else, opt for those in category 1, 2 and 6.