Thermoset vs thermoplastic coating – what’s the difference?
High performance coatings comes down to two broad divisions: thermoset vs thermoplastic coatings. The difference between them is chemical and determines how each coating cures. A thermoset coating cures irreversibly through the action of radiation, a chemical reaction or catalyst, or heat. Its molecules form crosslinks as it cures, combining to become long, tightly-bound polymers. A thermoplastic coating does not cure irreversibly but rather it remains plastic after curing. It has longer chain molecules to begin with than a thermosetting coating, and cures through the evaporation of its vehicle (either water or solvent) or heat (in the case of thermoplastic powder coating). A thermoplastic coating will soften if exposed to high enough heat.
Essentially the thermoset vs thermoplastic debate comes down to the properties needed in the final coating. In this article we look at thermoplastic coatings, how they are applied, some pros and cons, and the coating chemistries that include thermoplastic resin.
Thermoplastic coating application methods – power and hot dip
The most common method for thermoplastic coating is thermoplastic powder coating. Thermoplastic coatings are also commonly used for road markings and roof paint.
1. Thermoplastic powder coating
Powder coating is a process where a paint in dry powder form is applied to a substrate. The polymers most commonly used for thermoplastic powders are nylon/polyamide, polyvinyl chloride (PVC), polyethylene, and polypropylene. Generally, there are three basic methods of application:
- Electrostatic spray application – which is similar to conventional powder coat solutions. A powder is sprayed through a special gun which charges the powder for electrostatic attraction to the earthed surface. The dry film on the components is then heated to melt and flow. Note that not all plastics are suitable for this application method.
- Preheat spray application – The part to be coated is preheated, and powder is applied through spray application – the heat melts the powder immediately, rather than through a curing oven.
- Fluidised bed application – In this method pre-heated parts are immersed into a hopper filled with fluidised powder coating powder. The powder is attracted to the part and melts and flows due to the heat, though a post cure may still be needed. This method is also called thermoplastic dip coating or fluidised bed dipping.
2. Liquid-applied thermoplastic coating
Pavement and road marking paint and roof paints are liquid thermoplastics. They are designed to be applied thicker than paint which adds to their longevity. They can be ‘hot applied’ or ‘cold applied’. Examples of liquid thermoplastics include plastisol, which is a liquid thermoplastic dip coating, and in PVC and rubber roof coatings, which are spray-applied. Pavement paint and road markings are hot-applied coatings, and the heat helps the paint bond with the substrate.
Pros and cons of thermoplastic coating
There are reasons to choose thermoset coatings, and reasons to choose thermoplastic. Like any coating application, understanding the substrate, environment, and end use requirements is paramount to an effective and successful coating. For thermoplastic coatings, there are a range of qualities that make it suitable for some purposes but not others. We have listed them below.
- Pros: Thermoplastic coatings are strong, durable, flexible, impact resistant, chemical resistant, and waterproof. They also have high lubricity and adhesion as well as corrosion resistance.
- Cons: Because they do not form crosslinks, thermoplastic coatings may soften when heated. They are also more expensive than thermoset plastics.
Find thermoplastic powder suppliers and thermoplastic coaters in Australia
There is a wide range of substrates and uses for thermoplastic coating, and so it is no surprise that Australia has its fair share of thermoplastic coating suppliers and powder manufacturers. Below is a sample of the businesses providing thermoplastic coating services operating across the country. If you would like thermoplastic coating for your project, get in touch! Our experts are here to help. Take advantage of our expert advice and 100% quotes service and let us, in collaboration with our coating partners, connect you with the right coating for your needs.
|Thermoplastic Coating Company||Location||Services|
|Bayswater Plastic Coaters||Bayswater, WA 6053 (Perth)||Hot dip plastic coatings specialists.|
|Excite Powder Coating Services||Dandenong South, VIC 3164||Thermoplastic powder coaters|
|IBIX Special Cleaning||Newport, NSW 2106||Importer and distributor of thermoplastic powder coating equipment.|
|Impreglon Surface Technology Group||Minto, NSW 2566||Thermoplastic coating specialists, particularly thermoplastic powder coating.|
|Oxytech||Smithfield, NSW 2164||Thermoplastic powder coating suppliers|
|South East Superior Coatings||Coolum, QLD 4573||Thermoplastic coating specialists.|