What is powder coating?
You may have observed a number of your home appliances closely, which nowadays come with high quality painting. And why not? With the continuous subjection of equipment and appliances to extreme environments and conditions, whether it be household or industrial ones, it has become critical that the paint or coating applied to them can withstand all such scenarios. It is here that the powder coatings industry has really stamped its growth and popularity among end-users. Powder coating can be described as a type of coating, which is applied as a free-flowing, dry powder that may be a thermoset or thermoplastic polymer. The powder coating is generally applied through electrostatic processes, and cured under heat or ultraviolet light, as opposed to conventional liquid paint that is delivered through evaporating solvent. Powder coating offers a number of beneficial properties, which has made it a mainstay in a number of end-use sectors such as architecture, automotive, furniture, and consumer goods, among others. As such, a recent report by Grand View Research has stated that the powder coatings market will be worth USD 20.8 billion by 2028.
Types of powder coating material
The process of powder coating involves use of broadly two types of coating materials – thermoplastics and thermosets. Both these materials have a different set of characteristics; for instance, thermosets can withstand high temperatures, have a high scratch and mar resistance, require a cure cycle to harden, and are generally applied solely through the ESD method (we will learn more about this method shortly). On the other hand, thermoplastics can be reformed and recycled, have a higher impact resistance, do not require a cure cycle to harden, and can be applied via both ESD and fluidized bed method. Epoxy and polyurethane can be considered examples of thermosets, while acrylic and polyester are some notable examples of thermoplastics. There is also a hybrid variant of powder coating materials, known as epoxy-polyester. We will see a brief comparison of all these materials below:
| Epoxy | Hybrid | Polyurethane | Polyester | Acrylic | |
| Hardness | Very strong | Good | Fair | Good | Good |
| Exterior stability | Poor | Poor | Excellent | Excellent | Good |
| Ease of application | Good | Excellent | Good | Very good | Very good |
| Benefits | Highly resistant to chemicals | Offers certain ultraviolet advantages | Higher exterior durability | Good edge protection, thicker application | Good chemical resistance, good for clear coats |
| Disadvantages | Not UV-stable | Poor exterior durability | Requires high curing temperatures | May be unsuitable for thin films | Poor impact resistance, high costs |
Process of powder coating
The process of powder coating can be broadly divided into 3 phases – preparation, application, and curing. We will have a brief look at each of these stages below:
- In the preparation stage, the substrate surface is thoroughly cleaned to ensure that it is free of impurities such as dirt, dust, and debris. Some of the notable steps implemented at this stage include cleaning, rinsing, etching, blasting, and drying, while some of the widely-used equipment includes wash stations, blast rooms, and dry-off ovens. Wash stations are used in cases of removing oil, solvent, grease, and residue from the surface; on the other hand, surface debris such as scaling or rust are effectively addressed through blast room.
- Next comes the application stage. Here, the type of application method is determined by the type of powder coating material applied. The methods include electrostatic deposition (ESD) and fluidized bed powder coating. In ESD, the major components include a powder spray booth, electrostatic spray gun, powder feeder, and a power unit (depends on gun type). There are 3 notable types of electrostatic guns – Corona, Tribo, and Bell. The fluidized bed powder coating process, on the other hand, involves dipping of the preheated parts into the powder material within a fluidized bed.
- The next stage is curing, which again is determined by the method of application of the powder coating, as well as the type of material used. So, for curing ESD coated parts, a powder curing oven is utilized. The cure schedule depends on the size, shape, and thickness of the powder coated part. However, in general terms, an operating temperature between 325 to 450 degrees Fahrenheit leads to cure times in the range of 10 minutes, to over an hour. Moving towards curing fluidized bed coated parts, the heating is done before the coating application stage in a similar manner to that of ESD coated parts. Here, the parts can either be preheated before being passed through the powder coating cloud, or they can be heated and cured in a curing oven after coating.
Once all these processes are completed and the powder coated part becomes cool enough for handling, the part may be assembled, packaged, and shipped.
Benefits and limitations of powder coating
As mentioned earlier, powder coatings offer a number of benefits that have made the process highly popular among a diverse number of end-use industries. On the other hand, there are also some limitations that are attached to the process, which businesses need to be aware of. Some of these are discussed below:
Advantages:
- The major advantages over traditional liquid coating methods include an increase in durability, lower impact on the environment, reduced material costs, capability for highly specialized finishes, and a faster turnaround time.
- Powder coatings last longer and are more durable as compared to liquid coatings, demonstrating a higher resistance to moisture, impact, chemicals, and wear, while also being resistant to scratches, corrosion, and fading.
- In terms of environmental impact, powder coatings are considered to contribute positively in terms of lack of solvent, lower carbon dioxide emissions, and an overall lack of hazardous waste materials, thus making them an environmental-friendly option for liquid coatings.
- The process allows for the collection and recycling of overspray material, rather than wastage, thus lowering waste disposal, improving the utilization rate of coating material (experts state that material utilization is as high as 99%), and positively impacting the long-term material costs.
- The parts that undergo the powder coating process can generally be immediately assembled, packaged, and shipped, thus making them spend less time in the inventory, ultimately resulting in a faster turnaround time and alleviating high storage space requirements.
Disadvantages:
- A major limitation of powder coating includes difficulties in achieving an even coating, particularly for multi-color or thin coatings. Furthermore, the substrate material should be able to withstand the temperature requirements of the curing stage, in order to be suited for powder coating applications.
- Some parts typically require higher temperature and longer curing periods, which leads to incurring higher energy costs. This especially holds true for large, heavy, or thick parts, wherein it becomes more feasible to apply liquid coatings.
- Lastly, setting up the powder coating process is cost-intensive, with components such as specialized spray booth and curing oven particularly requiring substantial investments, which makes the operations unfeasible for startups and low budget operations.
Applications
When it comes to applications, the powder coating industry finds widespread utilization in sectors such as automotive, consumer goods, furniture, architecture, and general industries, among others.
- With regards to the automotive sector, high-usage car parts such as door handles, bumpers, window handles, wheels, and frames are just a few of the many notable parts that benefit from powder coating.
- Architectural steel parts, when powder coated, become resistant to heat and cold damage, as well as corrosion. Powder coating has been highly popular in the finishing of metal items since the 1950s. Additionally, metallic roofs and curtain walls also utilize powder coating, which maintains their appeal and appearance for a long duration.
- Powder coated products can withstand exposure to extreme environments, thus making them difficult to age and corrode. An excellent example is in use in road and direction signs, where they remain untouched even years after being erected, in the face of significant wear and tear.
- Powder coating has numerous other important applications, being used in tractors and farm machinery, as well as various industrial machineries. With industries looking to adopt more eco-friendly approach in the coming years, it is expected that powder coating will assume a more critical role.
- Household and office items such as lawn chairs, office chairs, desk parts, as well as other sundry products such as golf carts and cabinets, can be made to last longer through use of powder coating. The consumer goods sector has witnessed heavy growth in recent years, on account of the higher consumer purchasing power, as well as rapid urbanization. This has created numerous opportunities for the growth of the powder coatings industry.
According to an extensive study by Grand View Research into the powder coatings industry, the automotive segment is expected to show fastest growth through 2028 in terms of application. This is expected to be made possible by the growing demand for automotive accessories coinciding with the rising automobile production in major economies such as US, Mexico, Brazil, Indonesia, and China, among others.
How has the COVID-19 pandemic impacted the market?
Like every other industry, the coronavirus outbreak affected the powder coatings market competitors, especially as the industry saw numerous disruptions in the early months of the pandemic. However, the gradual recovery of economies around the globe have strengthened the belief that the industry will bounce back in the coming months. Below are a few key trends that have been highlighted during this period:
- The supply chain has suffered drastically, with the negative developments in the Chinese market, one of the major exporters of chemicals, having significant repercussions on the global powder coatings industry. The export of products that are utilized in powder coating process have suffered as China has used up many of the raw materials used for making coatings.
- The disruptions in supply chain have resulted in a subsequent increase in prices of chemicals, with major industry players such as BASF, DSM, DuPont, and LANXESS all having raised their prices. Examples include neopentyl glycol (NPG), used to prepare resins used in powder coatings, and triglycidyl isocyanurate (TGIC), a curing agent used in polyester powder coatings.
- The construction and automotive industries have suffered during the pandemic period, due to a mix of factors such as shutdown of operations and a lack of demand from consumers due to economic instabilities across economies. This is bound to impact the powder coatings industry; however, the gradual recovery of these industries over the coming months is expected to bring positive news for the market.
- The implementation of lockdown and social distancing norms, as well as work-from-home environment, has created a substantial amount of time for relaxation and recreation for consumers, as people have shifted their attention towards exercise and pastimes.
- Companies such as Lifetime, a recreational equipment manufacturer, saw increased demand during the pandemic period for recreational equipment such as playsets, kayaks, and basketball systems, which compelled them to turn towards George Koch Sons LLC for setting up a powder coating system to meet this demand.
- The increased focus on hygiene and sanitization brought about by the pandemic has created enough opportunities for major companies to bring products focusing on these aspects into the market. For instance, AkzoNobel added the BioCote antimicrobial technology to its Interpon D1000 and 2000 range of architectural powder coatings, which are used on a variety of surfaces.
- Similarly, KECO Coatings, a US-based coatings company, has come out with powder coatings possessing antimicrobial characteristics. The powder enhances products with silver ion technology, which provides bacteria-inhibiting properties to the coating during surface application.
Author’s Bio
Anant Singh is a content writer who takes a keen interest in the CMFE and Consumer Goods sectors, as well as all things technology. He currently works at Grand View Research Inc., a U.S. based market research and consulting company, headquartered in San Francisco, and has written a number of blogs and articles pertaining to various markets for the organization. Has also published reviews for TV shows on HBOWatch, where he is a guest writer.
Source: Grand View Research
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