As we explained in the first article in this series, plastics are usually made up of three or four molecules called polymers. These are long chains made up of smaller molecules, called monomers.
In this article, we want to answer the question: how is plastic made? We will go through the steps from raw material extraction, fossil fuel refining and hydrocarbon cracking to polymerization and processing methods.
The aim is to make you more familiar with what plastic is, its main ingredients and how crude oil is transformed into one of the most commonly produced materials on Earth.
Read more facts about plastics here.
1. crude oil is extracted and undergoes refining
The first step in producing any kind of plastic is to extract crude oil.
It is then sent to an oil refinery where it undergoes a series of treatments to transform it into various petroleum products such as gasoline, asphalt, aviation fuel, waxes and lubricating oils.
In the case of plastics, this is where the building blocks ethylene, propylene, styrene, and other monomers found in plastics are created.
2. Hydrocarbons are broken down by cracking
There are three specific methods for further processing of petroleum products after refining: thermal cracking, catalytic cracking and hydrocracking.
The word cracking comes from the English term cracking, which means decomposition and describes how heavy hydrocarbons with longer molecules are broken down into lighter hydrocarbons with shorter molecules.
It is this process that converts ethane and propane into ethylene and propylene.
3. Polymers are created by polymerization
Polymerization is the process of linking monomers together through a chemical reaction to form polymers.
After this step, ethylene is converted to polyethylene and propylene to polypropylene. Polyethylene is the most common thermoplastic and is mainly used in products such as kitchen utensils, toys, pipes, cables, plastic bags, plastic film and bottles.
Polypropylene is a thermoplastic that is durable, transparent and can withstand chemical stresses such as acidic foods being left in packaging for a long time. It is used in products such as food containers, packaging, toys, furniture and textiles.
4. The plastic is processed to create products
Manufacturing is the final stage where the plastic takes its final shape and where the plastic is transformed into different plastic products using different processing methods.
Some of the processing methods that we at Ösönerplast use are:
- Vacuum forming
- Laser cutting
- CNC milling
- Hot bending
Read more about the processing methods by clicking here.
To sum up: how are plastics made?
It starts with raw materials, such as natural gas, oil or plants, which are refined into ethane and propane.
Ethane and propane are treated with high heat, in a process called cracking. Then they are converted into monomers such as ethylene and propylene. Polymerization is the process of linking monomers together through a chemical reaction to form polymers.
A polymer mixture is heated and fed between two rotating main calendars. The pulp is pressed to a raw thickness and then rolled by subsequent rolls until the desired thickness is achieved. Then, for example, we at Ösönerplast shape them into a variety of products, including blister packs, plastic interiors, product displays, medical equipment and much more.
Read the previous post: What are the different types of plastic?
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