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New Technology for Plastic Powder Coating

Posted on: February 12th, 2018 by byersbushblog

Powder Coating Plastic

The art of powder coating is fast becoming the best way to coat high wear products and industrial equipment.  There are more and more powder coating services out there offering powder coating advantages.  Powder coating metals is relatively straightforward but what about plastics and polymers?  It is not so commonly known that alternative surface materials may be covered effectively in powder coating.  This enables the same high quality attractive finishes to be applied to just about anything.

powder coating plastic

Electrically Conductive

The question is how can you coat an item that is not electrically conductive.  Electrostatic charge is a fundamental part of the powder coating process. Non-metallic substrate can not be grounded as it doesn’t conduct electricity. When we perform the  traditional powder coating process, they rely on the metal substrate to draw electro-statically charged particles of polymer based powder onto the unit.  The unit is grounded in order to complete the circuit.  But what about objects like wood and plastic that are not conductive?  You can spray the powder on them but it will all end up falling on the floor.

Preheating

One technique that has proven effective involves preheating the piece you want to powder coat.  Put the item in the oven so that the surface becomes hot.  When you spray the polymer based powder at the item, these micro sized beads will slightly melt on impact adhering to the surface.  This enables powder build up on the piece.  You can repeat the process by returning the item to the oven shortly.  This will cause the powder coating to gel and an additional coating can attach itself to the surface.  Once you reach the desired thickness, the piece may be cured in the oven the same way you would normally set the powder coating.

spray-coating

Source: Yenra

Actually, it is usually the case that people put on too thick of a coating using this technique.  This happens because it’s hard to see clearly how much powder you have already put on the item.  The powder melts into itself like a gel coating making it hard to judge.  This is a concern because if a coating is too thick in some places it may begin to sag or run before the curing process can solidify the coating.  The coating may develop small craters that will effect the chip resistant properties of the powder coating.

Hot-Flocking

There is another method referred to as hot-flocking.  The concept behind this technique is instant coating.  You place the item into the oven and then preheat it to exactly the melting point of the powder coating material you will be using.  When you spray the unit polymer beads melt as soon as they touch the surface of the unit.  To accomplish this, you must spray coat the piece immediately after removing it from the oven.  This method takes quite a bit of skill and coordination.  The chances of running and sagging are greater when you do it this way.

Plastics That Can Be Coated

There are a variety of plastics out there that can be successfully powder coated.  These different plastics all have slightly different properties.  Some will be easier to coat in a powder coating than others.  Some can be preheated in the oven, but others require UV-cured polymers.  The UV lights do not generate the same amount of heat energy as an oven.

UV-curable polymers are a great solution for powder coating plastics.  The time it takes to melt these polymer particles is very short.  Since they melt quickly you don’t need much heat to push them into their gel-state.  As plastics are not generally conductive to electricity, an undercoat must be formulated for the powder coating process to work.  This primer will need to be customized so that is adheres to the plastic and works with the electro-static powder coating procedure.  We are happy to help you with this step of the process.  Please provide us with as much information as you can about the plastic based item you wish to powder coat.

nylon plastic powder coating

Source: Swagelok

Nylon reinforced plastic products require a specific coating technique.  To successfully establish protective coatings that improve the function and decorative properties of these items takes skill.  Products that rely upon nylon reinforced plastics are office chairs and appliances.  The interiors of our automobiles and some medical equipment utilize nylon reinforced plastic.  Consumer goods like personal computers and salon products also use nylon reinforced plastics.  Providing multiple colors and protective textures for these products is an important part of sales and branding.  These products often consist of both metal and plastic elements within their design.  The ability to coat then with the same polymer based powder coating is important.

Powder Coating Plastics: The Advantages

There are significant advantages to powder coating plastics rather than traditional painting techniques.  For one, the powder coatings emit little to no VOC or volatile organic compounds.  Traditional paints contain thinners that evaporate as the pain coating dries.  Additionally, over-sprayed powder can be recycled within the system.  This makes them better for the environment.  When you coat with polymer powders, you are able to achieve a thicker coating than liquid paints without the negatives associated with sagging or running paint coatings.  The coating is even.  Traditional paints show differences between the horizontal spray passes and the vertical spray passes.  Powder coating is able to create a variety of extrudes and effects.  Small items will hold a powder coat effectively letting you cover very small parts.

powder-coating-samples

Source: Inovoc Solutions

Technical Information

The performance properties of these coating technologies are interesting.  Different coatings hold different performance advantages.  Some are focused on being a protective coating.  Epoxy based powder coatings are generally used for the application. Polymer based can be formulated to provide UV protection for items exposed to the sun. Vinyl based powders are good for decorative purposes.

Application Methods

These powders can be applied using the typical powder coating process.  The item is hung in the middle of your spray booth and a pneumatic spray gun is used to cover the pieces with powder.   Plastic items may require a primer for the powder to adhere properly.  This system relies on the natural law of electro-static attraction.  The item will be grounded and the powder particles are electro-statically charged by the Corona spray gun.  The coating is applied and the powder is drawn to the grounded unit naturally establishing and even coat.  After the powder is cured, the item will have a strong plastic coating.  This type of coating resists chipping and scratching, preserving the items integrity.  The result is a durable coating that is soft to touch.

An alternative method involves building a tank that the part can be dipped into, then cured in an oven.  This process is also very effective and is generally used in an assembly line fashion.

Have A Question? Get In Touch With Us

Whether you need to powder coat industrial products or consumer goods, Byers Bush ready to help you.  We invite you to get in touch with us.  Powder coating is the best protection for many substrates.  Powder coating metal works well.  You can also powder coat plastics as well.  If you have any questions about the process or the item you wish to coat, tell us about it.

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