By
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2 minute read
Contents:
- Introduction
- Colour stability
- Age Embrittlement
- Dirt pick-up
Plastics are used in thousands of external applications. Many of the applications are successful and many are a failure. But what makes the difference between a good plastic and a poor plastic in external applications? Having spent the last 10 years studying the effects of UV degradation and different types of plastics and sealants, I can confirm that the material selection plays a huge part in the lifespan and success of the plastic when placed outdoors. In this article, we will study three main problems that we see on a regular basis when the wrong material is chosen for an external application:
Colour Stability
Colour stability is one of the first things you will actually notice and some colours are harder to stabilise than others. Unfortunately, yellow is the single hardest colour to stabilise and so it takes a very stable polymer to prevent colour fading with a yellow product. Take a look at an ambulance wind deflector that’s more than a couple of years old. Often this will have faded well beyond its original Ral 1016.
One of the next hardest colours after yellow is red. You can see evidence of this on Royal mail post vans as some of its different plastic components fade to a shade of pink. Colour stability is measured using ASTM G154. You can find more on this standard here.
One of the most colour stable materials we have seen is PVC (Polyvinyl Chloride). This is used in many external applications including windows, doors and flexible industrial barriers.
Age Embrittlement
Similar to colour stability, age embrittlement can happen from the wrong material selection. Some plastics are far worse than others for becoming brittle over time. You can find this with plastic clothes pegs where you may also notice they break easily after time. You may find that particular colour clothes pegs degrade faster than others and this is largely due to the pigment loading in the product, Heavy pigment loading results in a weaker peg. PVC is used in many industrial applications where long-term durability is essential. In this image below, you can see a PVC capping being fitted to a home delivery van, this capping is essential in maintaining the integrity of this vehicle.
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Dirt pick up is a subject discussed by automotive , marine and many other industries. It is particularly prominent in the sealants industry and there are few manufacturers that know how to handle this problem. The number one cause of dirt pick up is the porosity of the polymer (in other terms, how much liquid can pass through tiny holes in the material). On the surface the polymer may seem like a smooth plastic, but at a microscopic level, there are pockets which allow dirt entrapment causing the plastics to appear dirty very quickly. PVC is often used for clean room cladding and surgery clothing due to the easy clean properties.
If you are looking for a suitable barrier system for an external application, then PVC may be a great choice for you. If you have a project and you’re ready to reach out, we would love to help you and give you specific pricing for your project. Ultimately the choice of which barrier system you choose rests with you but the purpose of this article is that you can make an educated decision without bias.
