Paint is a highly competitive industry. The leading paint production companies spend millions of dollars in research and development each year. They are consistently looking for any way that they can improve their product offerings and find new paint applications. One area in particular has received a fair amount of attention: paint filler material.

All paints and coatings use filler material in addition to resin to create the final product. The issue with many of these filler materials is that they have irregular shapes on the microscopic level. The irregular shapes will leave gaps in the paint, which will be filled in with additional resin. This leads to paint formulations that are difficult to spray. Additionally, inefficient filler materials can cause paint coatings to run or sag when applied.

One filler material in particular has been able to solve the issues that are present in older filler materials, microspheres.

Microspheres as paint fillers

Microsphere popularity has grown in many industries, from fiberglass to mining explosives in addition to paint. The class of materials has enabled new product development in addition to lower costs. There are a number of physical properties that make microspheres a perfect filler material for paint.

Attractive properties of microspheres

Hollow microspheres are small spherical microparticles. The diameters of microspheres can range from 1 μm to 1,000 μm, but microspheres for paint applications generally range from 12 to 300 μm in diameter. There are a number of microsphere materials that can be used in paint formulations, such as glass and ceramic.

When microspheres are used as a filler material, the amount of resin required is reduced. Spheres will always have the smallest surface area for any given volume. The result of the small surface area ensures that there are few gaps in the finished product. Less gaps in between the microspheres translate into less resin required in the final product.

The large volume that microspheres take up along with their low density, also play a part in lowering the density of the final paint product. The lower density of the final paint coating reduces the weight. The tight particle packing of the microspheres also will result in a phenomenon called the barrier effect. This phenomenon consists of the formation of the vitreous layer. This low-permeation film barrier protects the surface of the material from the effects of elevated temperatures as well as corrosion.

Ceramic microspheres are also inert, which gives the paint more resistance to certain chemicals. Additionally, microspheres are an extremely stable shape, which increases the amount of force that the paint can endure. The final paint coating is also easy to wash and scrub as it has more resistance. Microspheres provide lower viscosity, better flow, and improved sprayability in the paint coating.

Microspheres also have the ability to be coated in other materials, such as silver or silane, which give them incredibly interesting properties. Coated microspheres are changing what is possible with paint and pushing the entire industry forward. One really interesting application of coated microspheres is a paint that can light up like a neon sign.

Coated microspheres for electroluminescent paint

Coated microspheres can be used to create an electroluminescent paint coating. Electroluminescence is a phenomenon where a material emits light when an electric current is passed through the material. The principle is simple, but creating a paint system that is electroluminescent has a number of hurdles.

Getting an electrical current to flow through paint is a difficult task. Paint is not typically a conductive material that an electrical current can easily flow through. Silver is the perfect material to enhance the conductivity of the finished paint coating. An underlying problem is that silver is an extremely expensive material.

Silver coated microspheres are a great solution to the issues of conductivity and cost. Silver can be electroplated onto glass or polymer microspheres. This drastically reduces the amount of silver required for the end application. The overall cost of silver can be reduced by 3,000% if the paint and coated microspheres are properly formulated.

The level of conductivity is also reduced when the silver is coated onto the microspheres, yet the conductivity is still high enough to permit the passage of electric current through a coat of paint. When an electric charge is applied to the paint coating, the paint will light up much like an LED. The electric charge stimulates the crystals in the material and emits light.

It is clear that microspheres and coated microspheres open up new paint applications. Paints and coatings can benefit greatly from the continued addition of microspheres. These microsphere technologies will set paint companies apart from each other as they learn to continue to utilize coated microspheres.