Our modern world is filled with plastic, a hugely versatile and useful material. From food packaging to space rockets, plastic has enabled many of our advances and conveniences.
This commonality often has us overlooking the obvious: there are many different plastics. Knowing which is the right plastic for your project is important, as we discuss in our blog post, How to choose the best resin for your plastic product.
Resin is the core ingredient for all plastic products. But where does it come from?
The origins of plastic
Plastic is made from the byproducts of oil refinement. When crude oil is extracted from the earth, it is a mixture of many different chemicals. To get to the various substances we use every day, the crude oil must be distilled. This is done by heating the oil, allowing different chemicals to separate and be collected.
Some of these liquids can be used to create plastic once they are altered through a process called cracking. Basically speaking, plastics are the result of molecules called hydrocarbons being encouraged to create chains, called polymers.
To create these hydrocarbon chains, a compound (or monomer) such as ethylene (also called ethene) is placed under heavy pressure and mixed with a catalyst until it forms a liquid that eventually becomes the plastic pellets aka. Resin. In the case of using ethylene, we get polyethylene. PVC is made using the compound vinyl chloride.
The process of making plastic can be altered in numerous ways, leading to a lot of variety even among common plastics. For example, polyethylene plastics make up everything from supermarket bags and water bottles to hardened gun cases. Polystyrene is best known in its brittle form marketed as Styrofoam, but it is also used to create toy figurines and CD cases.
Most resins aren’t just the raw ingredients from the creation process. Additives are added during the polymerisation process to alter the properties of the plastic even further. How well a plastic hardens, resists heat or exposure, or even its colour, is often determined with additives.
But even with these extras thrown in, once crushed into beads these plastics are still called resin. The beads are added to any plastic molding or baking process, creating all the plastic products around us today.
Yet while it is good to know how resin is manufactured, it is critical to know what properties you need for your final product. Consult our injection molding experts at Plastinternational today with your specifications and make sure you get the right stuff for the job.