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Thermoplastics: The Genie is Peeking Out of the Bottle

MONDAY, JUNE 18, 2018

By Warren Brand

You heard it here first, folks. Paint is dead. It just doesn’t know it yet.

I’ve been involved in the coating industry since I was around 9 years old. My father was one of the first franchisees in the country, applying some of the first 100-percent-solids epoxies developed in the late 1950s. For some of us gray-hairs, that was with Paul Meli Jr., for whom I had the privilege of writing a tribute when he passed away in 2016 at age 93.

My version of summer camp was riding around in panel vans, helping workers apply these emerging coating systems to the exterior bottoms of 275-gallon oil tanks in residents’ basements, and post-curing them with UV heatlamps.

Since that time, I’ve been a contractor, owned a contracting company and personally sandblasted and applied hundreds of different types of coating systems—and have been involved in supervising or providing professional consulting support for many thousands more.

Currently, I provide vendor-neutral corrosion-mitigation consulting, optimal materials identification, site-specific application specifications and supporting services. Our business model is simple: Do first and foremost what’s exclusively in the best interest of the client.

This business model has kept me on the lookout for what’s new and well-vetted for the benefit of our clients.

And I’ve been waiting and wondering for decades when someone was going to figure out how to apply thermoplastic materials in the field.

And just over these past few months, we were involved in two different thermoplastic applications in Chicago-area swimming pools. But first, a note about:

Thermoplastic vs. Thermoset

The simplest way to think about thermoplastics and thermosets are to visualize candle wax (thermoplastic) compared with a two-part epoxy paint that has cured (thermoset).

Thermoplastics can be melted again and returned to their original condition. Thermosetting materials cannot.

Paints and coatings are thermosetting materials.

A Tale of Two Steel Swmming Pools

Let’s dive in:

Pool 1

The first pool was interior-lined with a thermoplastic several years ago. Our client was the board of directors of the condominium association. What they first thought was staining on the material turned out, in fact, to be holidays, allowing rust to “bloom” up through the coating system. 

Swimming pool with thermoplastic lining
All photos courtesy of the author

The first pool was lined with thermoplastic (see inset) years ago and was exhibiting rust "staining" (noticeable in main image at left).

Rust bleed

What was thought to be staining was in fact rust bleeding through holidays in the coating; in some areas, the plastic globules weren't flattened enough on impact.

It appeared that the material was applied too thin in these areas and that, perhaps, the applicator was a bit too far away, allowing the molten droplets to cool a bit too much before hitting the substrate—or the substrate was not at a sufficiently high temperature.

Thermoplastic coating

An area of the pool that was better applied: The thermoplastic material flattened and looks like fish scales.

Either way, the low-voltage holiday detector was chirping like a starving chick in all of those areas where the board had thought the coating was stained due to rust coming out of the recirculating piping system.

Pool 2

For the purposes of complete clarity and disclosure, we were professionally engaged to assist with the second pool, with a different contractor and similar material and application technique.

Pool 2: inspection

The author's firm advised on Pool 2 and introduced QC protocols including holiday detection and surface-profile and DFT monitoring during application.

Thermoplastic application

The second pool was subject to spray application of thermoplastic material.

To make a long story short, the fact that we were there in an advisory capacity, and used the holiday detector during application, the installation appeared better and, hopefully, will last in excess of 10 years with little to no maintenance.

Thermoplastic coating

Proper application exhibits the fish-scale texture. (This image is from prior to the final application.)


Pool 2 after its return to service

Time will tell—which is the nature of technology on the “bleeding edge of development.”

What the Genie Looks Like

Thermoplastic materials are everywhere. Much of the car you drive is made of them. The ubiquitous red Solo cup is as well. Water bottles, milk cartons, insulation on wires, almost everything plastic is, by definition, thermoplastic. And many powder-coating systems have been thermoplastic for years.

Depending on the formulation and makeup of the material, they are durable, UV-resistant, color-stable and repairable, and offer varying degrees of moisture permeability. In terms of performance, they appear to be competitive with most paint systems applied in atmospheric exposure, such as those on bridges, railings and other commercial and architectural applications.

And, there’s no cure time. Let me repeat that. Once the kinks are taken out of the application process (as the performance characteristics of the materials are already well understood), there will be no cure time at all.

Picture, for example, a bridge covered with a plastic-like material that is durable, color-stable and will last for decades with little to no maintenance. And to repair it, simply add more flame-sprayed material—there may be no additional surface prep required.

Some formulations of thermoplastics are so durable, they are being used as an alternative to traditional road-marking paints.

Or, take the lowly plastic water bottle (polyethylene terephthalate, or PET for short) for example. Water bottles are an environmental scourge. They are everywhere and, depending on who you talk to, take 450 to 1,000 years to biodegrade. Imagine, for a moment, having the ability to take used water bottles, process them into powder or pellets and install the PET to tank interiors—or tinting them and installing them, well, everywhere. In one process, we’ve found a solution to recycling PET and putting it where a 450-year service life is of value.

The Problem Has Always Been Deposition

Historically, thermoplastic materials have been injection-molded. Small polyurethane (for example) beads are dumped into a machine, which melts and injects the molten goo into a mold, making everything from bumpers to iPhone cases and canoes.

Another means of deposition, or application, is taking parts and having a powder electrostatically applied to the part (chairs, railings, etc.). Once the plastic powder has been applied, the tool is sent into an oven for heating and melting of the powder.

In both cases—injection molding and electrostatic adhesion—the materials remain pure and unadulterated.

The problem in field applications has always been deposition: How do you get the plastic melted onto a substrate?

The current process is relatively straightforward in concept, but highly complex in implementation. Much like sandblasting is simply injecting an aggregate (sand) into a shrouding gas (compressed air), current technologies of thermoplastic application inject plastic powder into a stream of flame. The powder melts and is “splattered” onto the substrate.

The problems with this process, however, are many. First, the flame adds a myriad of contaminants and a ton of uncertainty into the process. It inserts gases of combustion and oxides and modifies the polymer in ways that other means of deposition or molding don’t. These variables may change the performance characteristics of the material in ways that are impossible, or at least difficult, to anticipate. Further, regarding application, there are other variables as well, such as the ambient temperature of the substrate, maintaining the substrate at proper temperature during application, how far to hold the nozzle from the surface and at what angle, and how thick the material can be applied at a pass in order to get the right thickness.

Currently, from the pools we were involved with, the application is tricky and labor intensive. Surface prep is the same for paint, a White Metal (SSPC-SP 5/NACE 1) or Near White (SSPC-SP 10/NACE 2) with an angular profile. Two coats of a polymer primer are applied, followed by a tack coat of thermoplastic and two additional coats.


There are two types of obstacles I foresee: technical and business.

Potential technical obstacles for thermoplastics:

  1. Will these materials perform as anticipated after being subjected to a shrouding gas and the inconsistency of human applicators?
  2. How well will they adhere to varying substrates and how long will they last?
  3. What is their permeation rate and will they resist osmotic blistering?
  4. Will they be too soft for some applications?
  5. How will the materials perform on edges (beveled or otherwise)?
  6. Will there be any health or safety issues with the application?
  7. Will the production rate be sufficient to compete with traditional liquid-applied polymers in various applications?
  8. How much will it cost?
  9. How will it be repaired?
  10. Are there risks in removal and disposal of the material at the end of an asset’s lifecycle?
  11. What technical unknowns will crop up as the technology matures?

Potential business obstacles:

There’s only one—big paint will not sit idly by as this, or any other technology that has the potential to substantially erode market share, takes hold. I have thoughts on what might happen from a business perspective, but they are not relevant in a technical blog such as this one.


I’m a dyed-in-the-wool skeptic when it comes to pretty much everything, particularly in our corrosion mitigation field. My other company provides business development support to companies trying to market new materials within the corrosion protection space. And I’ve seen many materials that simply don’t pass muster. In most cases the owner or inventor has fallen in love with their material and are unable to see the competitive challenges.

But thermoplastics is a completely different ballgame.

The performance characteristics of these thermoplastic materials are exceedingly well understood from having been used for decades in other applications. These systems are durable, repairable, UV-resistant, VOC-free and readily available. And if recyclables, like PET, can be turned into field-applied coatings, material costs may be staggeringly low.

Keep an eye on the genie. It may change our industry forever.


Warren Brand

Warren Brand’s coatings career has ranged from entry-level field painting to the presidency of two successful companies. Over nearly three decades, he has project-managed thousands of coating installations and developed specs for thousands of paint and coating applications. NACE Level 3 and SSPC PCS certified, Brand, an MBA and martial-arts instructor, now heads Chicago Corrosion Group, a leading coatings consultancy. Contact Warren.



Tagged categories: Coating Materials; Consultants; NACE; Protective Coating Specialist (PCS); Protective coatings; Specification writing; SSPC; Asia Pacific; Coating chemistry; Coatings technology; EMEA (Europe, Middle East and Africa); Latin America; North America; Thermoplastic

Comment from Christopher Gatian, (6/20/2018, 10:42 AM)

Great article! The technical obstacles don't appear to differ much from those already encountered with thermosets. The listed advantages over thermosets make thermoplastic systems seem quite appealing. How much research has been done? I'd like to see how certain properties, like adhesion, compare to thermoset systems.

Comment from Dana Stiles, (6/20/2018, 10:36 PM)

Great article - the current flame-gun application method for thermoplastics like abcite is still a limit, I wonder why they can't use hot air. I have long been interested in PU and PUR coatings, but I believe that site applied thermo-plastics has good promise.

Comment from Warren Brand, (6/21/2018, 12:41 PM)

Hi Chris. Thanks for your kind words. I don't think very much research, on a high-level, has been done yet. When we got involved in our project, the vendors involved didn't know what Holiday testing was. Not an uncommon occurrence when you're used to applying to concrete. I'm also eager to see how the technology progresses.

Comment from Warren Brand, (6/21/2018, 12:43 PM)

Hi Dana. I had the same thought - about using hot air. It would impart no contaminants. Good promise, indeed. I'm excited to watch its progress.

Comment from William Feliciano, (6/28/2018, 10:38 AM)

I write and review coating specs for a transportation agency. Thanks for the well-written, interesting article. I don't have much exposure to the thermoplastic industry, so suffice to say I have too many technical questions to post here. As most know, steel bridge painting is solidly controlled by liquid applied coatings sector. Yet the sustainability aspects of thermoplastic are intriguing. Hopefully great strides in application technology are made and, more importantly, are made known outside the sectors where thermoplastic is currently employed.

Comment from Warren Brand, (6/28/2018, 12:10 PM)

Hi William. Thanks for taking the time to comment, and for your kind words. Agreed, I'm very eager to see how the technology develops. My first thought when reviewing the technology was for bridges. But, like you, there are too many unknowns and variables.

Comment from Arvind Kr Gupta, (7/2/2018, 1:01 AM)

Great article, however how much time it will take India to replace the conventional paint Industry? Is thermoplastic coating technology available in India? Any Guesses .

Comment from Warren Brand, (7/3/2018, 11:23 AM)

Hi Arvind. Thanks for taking the time to post. I have no idea. As I mentioned in the article, there are two types of obstacles, technical and business. The irony is, the better performance characteristics of the technology, the more likely big paint will take steps to squelch it.

Comment from Dana Stiles, (7/5/2018, 1:17 AM)

Hi Warren, I would sincerely hope that the squelch comment does not prove to the case. I work for a company owned by a paint manufacturer, and one of my colleagues in another division is working on this technology, and I have seen a demo - suppled some epoxy primers for concrete application. I know there will always be "channel conflicts" within businesses, but hopefully solution based organizations will embrace new and better technology solutions. Best Regards

Comment from Dave Wonnacott, (7/6/2018, 6:10 PM)

Surface prep with gelled acids (Surface Gel Tek) preheated surfaces with portable radiant heaters designed for the purpose, and good training of the applicator , will go a long way toward success. Basically, as you sort of referenced, field powder coating. I used to hire art students at Arizona State Univ. as operators of powder coating and commercial multicolored silk screening as they already had the hand/eye coordination and lived for the successful quality and beauty of the finished result.

Comment from Wayne Senick, (7/24/2018, 3:42 AM)

The Genie was out of the bottle in 1993 when we used a product supplied by Plastic Flame Coat Systems of Big Spring Texas, they now are called Protech Powder Coatings. They are now only in the Raw Material Supply business. In the early 1990’s they were spending allot of money developing a system for field application of their thermoplastics powders. We became a distributor and certified applicator for the Plastic Flamecoat Thermoplastic powders and field application equipment. We coated Vehicles, steel components and bridges. The largest Bridge we did was the Splash Zone on the Arlington Bridge in Winnipeg Manitoba. Using the Flame Sprayed Thermoplastic powder was a great idea because of its durability and abrasion resistance. The problem was getting a uniform application and getting the proper film thickness was difficult. The coating is still on the bridge after 25 years and in the areas where it was applied at the proper film thickness is still performing. Areas where it was applied to thick cracked but in most cases did not peel off. On a visit to the city engineering department two years ago we were discussing bridge coating and one of the engineers who was new to the department asked me since we were there when the bridge was coated in 1993, if I knew what that plastic stuff was that is applied on the splash zone. They tried to blast it off to do some repairs and they could not blast it off. It is tough stuff if you get it on right. Here lies the rub one of the biggest problems we had was fluidizing the powder so it would flow uniformly to the flame thrower, so we could get the plastic to melt and apply it at a uniform film thickness. On the bridge because of the geometries it was difficult to get a uniform film thickness because of the inconsistent flow of material. Once the fluidization and transport to the nozzle problems are solved this will be a viable high performance alternative abrasion resistant anti-corrosive barrier system.

Comment from Rosemary Coutinho, (7/27/2018, 9:49 AM)

Excellent article! Congratulations! This kind of corrosion protection seams to be a great evolution if the problems around it were solved.

Comment from Nick Hodgson, (7/30/2018, 1:27 AM)

Very interesting article, thanks Warren. Can think of many applications where this has merit over conventional coating systems. Any idea on the upper temperature limits when in service before they start losing form again?

Comment from Warren Brand, (7/31/2018, 11:48 AM)

I owe an apology to Dana, Dave, Wayne, Rosemary and Nick. I thought I would be notified when responses were posted. Thank you all for your input. Dana, I hope you're correct! Dave, very cool and interesting, thanks for sharing. Wayne, not surprised you were involved in a cutting-edge project like this. I think they're close to getting the kinks out. Rosemary, thank you. Nick, I liken thermoplastic technologies to the early days of metallizing, where the only thing that could be sprayed was zinc and aluminum. And now almost any metal can be sprayed. The upper limit of any thermoplastic will be it's melting point or glass-transition point. The problem is the melting point is reached gradually, and the polymer will lose some of its functional characteristics as it approaches its melting point. This is likely less of an issue for structural steel, bridges, etc. But as the technology evolves, and uses broaden, it will become critical. For example, I can foresee a day when thermoplastics are used for tank interiors, but great care will need to be taken to determine ambient temps within the tank. For example, a thermoplastic might be 100% fine and NSF approved for cold water. And may be functional for hot water, but NOT, NSF approved, as the hot water may be too close to its melting point, allowing compounds to be released. Thanks again to all for taking the time to read this, and other blogs, and more so for taking the time to comment.

Comment from Charles Sulivan, (1/15/2020, 5:17 AM)

Epoxy Flooring is the best finish you can ever have on your house.

Comment from Katie George, (9/8/2020, 3:08 PM)

A common problem we're running into now is with all these new guys offering soft washing. Everyone knows that bleach is a corrosive and that when sprayed on roofs it will rust out the flashings in the eaves -

Comment from Katie George, (9/8/2020, 3:10 PM)

A common problem we're running into now is with all these new guys offering soft washing. Everyone knows that bleach is a corrosive and that when sprayed on roofs it will rust out the flashings in the eaves -

Comment from Nguyen Tung, (10/1/2020, 1:27 AM)

Thanks your article. But I think In practice, the application of floor paint is not easy with the Thermoplastic. Our company allway used expoxy coating for congrete floor as primer. Then we applying Acrylic coating (Son 2k) or pu coating (Son pu) as top coat

Comment from Derek Kilfoy , (12/27/2021, 9:02 PM)

Does anybody know how many kg the 2 inch 200 series PFS plastic flame coat systems back pack or tri pod system applies in 1 hour

Comment from Derek Kilfoy , (12/27/2021, 9:04 PM)

I just recently bought one that has never been used,I think it was manufactured in 1993

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