Bringing particle size analysis to the powder coatings production line

Look around the room, and you’ll see that most items and objects have a coating: a coat of paint to make a chair look nicer, for instance, or varnish to protect a table. For decades, solvent-based coatings have been the norm, but with an eye on sustainability, manufacturers are increasingly moving to powder coatings instead.

The reasons are simple: powder coatings are easy to apply, avoid the waste and health issues linked to liquid solvent-based coatings, and provide an aesthetically pleasing, durable finish. Manufacturers usually purchase and process these coatings in batches: the objective is to make use of every batch while precisely maintaining the same output quality.

How can they achieve this? Read on to learn about the importance of particle size analysis – and our laser diffraction solution bringing high-precision analysis to the production line itself.

Why does particle size matter for powder coatings?

Particle size affects many properties key to a successful powder coating application. One of the most important is processability. An even distribution of small particle sizes is crucial to a smooth curing process – and in turn, a smooth surface. Smaller particles melt, flow, and meld together faster and more evenly, so the process is faster, requires less energy, and results in higher mechanical strength and chemical resistance.

Another benefit is that when the powder is made up of smaller pieces, more of the particles are exposed to the surface, improving the adhesion of the powder to the substrate. The powder is also used more efficiently, minimizing overspray.

A tight hold on particle size distributions, which can vary between batches of powder coating, is therefore crucial for both the application process and the result. Traditional sizing methods, like sieving, provide only an approximate measure of particle size: laser diffraction is the solution.

The benefits of laser diffraction

Laser diffraction measures particle size distributions by measuring the angular variation in the intensity of light scattered as a laser beam passes through a particulate sample. Large particles scatter light at small angles relative to the laser beam, while small particles scatter light at large angles.

Laser diffraction instruments like the Mastersizer 3000+ use this data to automatically calculate the size of the particles. They are therefore very easy to use, don’t require anything near the time and effort of traditional methods, and provide much more rigorous and repeatable measurements.

This technique is already routinely used in the powder coatings industry, especially within the lab environment for product development and quality control purposes. But what if, instead of bringing samples from the production floor to the lab, laser diffraction could be performed within the process line itself?

Real-time particle size analysis with Insitec

Insitec is a fully automated and on-line laser diffraction system, enabling real-time monitoring of particle sizes during the powder coating production process. Operators can see the consequences of milling, for instance, ensuring that every batch complies with tight particle size parameters, and helping avoid over-milling.

A typical powder coating manufacturing facility contains 10 to 15 process lines, and using a single instrument for each line is essential to achieve the best results. Until now, such systems have not been economical to install across multiple lines – but this has been resolved thanks to Insitec’s cost-effective ‘plug-and-play’ capability.

This is achieved thanks to a tailored on-line monitoring package specifically for powder-coating customers. With a two-mode operation, plant managers can monitor particle sizing continuously during the initial stages of a milling run, and follow this with discontinuous monitoring to minimize waste and keep costs down.

With this package, Insitec provides an overall productivity improvement of up to 5%, and corresponding cost savings. With laser diffraction accessible for both the lab and the production line, manufacturers can maximize product quality while keeping a competitive edge.

If you’d like to learn more about our laser diffraction solutions, please sign up to our upcoming webinar! And don’t forget to download our new white paper, titled “From in-lab to on-line: Versatile options for particle size analysis of powder coatings using laser diffraction”