Guest editorial: Moving formulations and technologies forward

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by Perry Poppelaars – MD of Sustainable Coating Solutions Ltd – Distributor for Steelpaint in the UK

My coatings career started in 1984 with Devoe Coatings, an American manufacturer of marine coatings and the first company to introduce epoxy coatings. The first job I did for them was supervise the coating application during a drydocking of a VLCC (Very Large Crude Carrier) for an oil major. Four truckloads of Chlorinated Rubber paint were applied to this one ship. The average Volume Solids content of CR-coatings was 35%. Just imagine, two thirds of the paint actually evaporated into thin air. I can still remember the smell around those drydocks.

Regulation of the use of hazardous substances and the ban of certain raw materials, such as e.g. trybutil tin (TBT) from antifoulings in 2003, have forced the coatings industry to constantly adjust and improve their product formulations and technologies. This is an ongoing process aimed to improve health and safety conditions for users and the reduction of global warming in a broader sense.

The desire to extend the life cycle of steel structures up to 50 years creates another challenge for the coatings industry to develop systems that are actually capable of providing long term corrosion protection, in order to reduce overall maintenance and therefore lifecycle costs.  Over the past decades extremely demanding test regimes have been established to evaluate the performance of coating systems for the various environments.

The future decade will most probably be the last of my active participation in the coatings industry. It will be interesting to see how things further develop, but I would like to raise a red flag where it concerns the testing regimes for coatings in relation to maintenance projects.

First of all, most of the tests are based on application of the paint under laboratory conditions. Conditions which are very unlikely valid during the execution of a maintenance project in the field. Then the surface preparation standard for testing is usually SA2.5. Reduced preparation standards are quite common on maintenance projects nowadays. An exception is the Network Rail Standard in the UK, which has a testing procedure over reduced surface preparation with an expected performance lifetime related to it. However, the message is: many coating systems will pass a laboratory test regime but may fail in practice due to uncontrolled ambient site conditions site or reduced preparation standards.

The testing of coatings has become an industry by itself. It is very expensive to test coating systems, no matter where or for what purpose. But without an approval no sales. There is no escape, if the proposed system fails the test, money gone, back to the drawing board. Most of the tests use the ISO 12944 as the main guideline for the requirements and procedures. So, my question is why not establish one general global testing regime for coatings, or at least a European Standard. There are only so many things you can test on coatings. Why repeat the same thing over and over again under different testing regimes. The money and time wasted could be spent on research and development of innovative technologies and drive the industry forward faster.

Lastly there is the fact that the coating system itself is just one part of a paint project. Paint is a half-product. The end product is established on location by third parties under variable, unpredictable conditions. This makes the next question valid: By enforcing strict test regimes, the expected life time and quality of coating systems have become measurable and are evaluated accordingly. Which is a good thing. But how are the quality and viability of a bid and the execution thereof measured? Representing the other part of the end result.

It seems to me that in a lot of cases the number on the bottom line in a bid is the main decision maker. Leaving certain variables out of the equation may result in an attractive bid. But during the course of a project will add to the unwelcome surprises extending the running time and overall costs of a project.

I have been in many situations where, due to poorly prepared bids or over-optimistic planning, projected quality standards had to be abandoned during a project, under pressure of time and budget. Almost without exception the consequences end up in the courtyard of the coatings manufacturer, who is still expected to hold his end of the bargain where it concerns life expectancy statements or performance guarantee contracts. In short, the responsibility and risk is put on the smallest player in the project team.

The  best way to protect yourself as a manufacturer is to designate a few representative reference areas (on any project), which are fully prepared and coated according to specification, whereby every step of the process is monitored and signed off by all involved parties. Future failures will then  be compared with the reference areas. In this way responsibility can always be put where it belongs.

Coatings innovation – Steelpaint

In the past I was privileged to work for two coating manufacturers who have brought true innovations in coatings technology which were then followed by the whole industry later. Devoe, who as a first introduced epoxy coatings and the first self-polishing tin-free antifouling. Ameron the inventor of ethyl zinc silicate and later polysiloxane technology.

Under the banner of Sustainable Coating Solutions Ltd I am very proud to currently represent Steelpaint GmbH in the United Kingdom as exclusive distributor. Steelpaint is another coatings manufacturer who very recently has managed to develop truly innovative coatings technology with enormous potential.

Steelpaint has been a leading manufacturer of Moisture Cure PU coatings for over 30 years. The company has always strictly focused on the production and development of MCPU coatings. Aiming to be the best in this niche of the coatings industry.

MCPU technology was originally invented a few decades ago by Bayer Material Science (now Covestro) from Germany. The most striking difference to epoxy coatings is that, instead of adding two components together, the curing process is initiated by the reaction of the polyurethane binder system with atmospheric moisture (measured in percentage Relative Humidity). A very positive consequence is that moisture cured urethanes can be applied up to 98% relative humidity. Surface moisture actually completes the chemical reaction, as a result these coatings show excellent adhesion to visibly damp (not wet) surfaces.

  • MCPU coatings will cure down to minus 5°C without any additives. Heating and dehumidification therefore are not required during application. This presents a significant reduction on energy costs.
  • MCPU coatings provide longer corrosion protection at a lower film thickness. A typical total film thickness of a coating system for bridge in a C5-M environment would be only 240 micron. This results in a considerable weight reduction and longer maintenance cycle.
  • The polyurethane binder ensures permanent flexibility of the entire coating system. This resists cracking of the coating on stress areas. Less corrosion, less maintenance.
  • MCPU coatings are surface tolerant, which means that they can be applied over a reduced surface preparation standard. For example, over St3 (power tool) prepared steel a minimum life expectancy of 15 years can be obtained. In combination with alternative surface preparation methods not producing spent abrasives, e.g. CO2 blasting or RPR Heat induction, it is possible to achieve significant savings on project costs. The absence of tons of spent grit allows lighter scaffolding and reduces waste removal costs. Only the removed corrosion product and paint waste need to be collected and removed.
  • When overcoating aged coating systems, or itself, it is usually not necessary to abrade the existing system. Reducing preparation costs.
  • MCPU coatings are single-pack products. Once opened the pails can be used for another three days when properly closed. This reduces the risk of mixing errors and wastage.

 

Because Steelpaint have only focused on MCPU-technology it is only logical that they have taken the industry lead to bring MCPU technology to the next level.

A paint formulation is a living thing. Under pressure of price, performance, environmental regulations, availability of raw materials etc. coating formulations are continuously under revision.

Whereas price and performance of a coating can be influenced by the manufacturer, environmental regulations are a given because they are laid down in legislation.

For the coatings industry the two most important items of concern are the content of VOC’s (Volatile Organic Compounds), and the use of raw materials causing an environmental threat or a health and safety hazard to the user.

Presently Steelpaint’s traditional MCPU Stelpant coatings are well within legislative guidelines, and will be for the next decade or more. But this situation may likely change one day.

The curing mechanism for all polyurethane based coatings is Isocyanate. The Isocyanates used in Steelpaint products present, in observance of current industrial safety measures and parameters, no health hazard. Nevertheless Isocyanates and other raw materials, such as Bisphenol and Epichlorohydrin in epoxy coatings, are under scrutiny.

In view of the European GHS/CLP regulation not only the labelling for isocyanate containing products has been sharpened (with unaltered hazard potential), which understandably has raised concern with applicators. The EU is also planning the introduction of a proof of qualification for companies that are working with products which contain Isocyanates of any kind (also in sealants and foams etc.).

To stay ahead of this discussion Steelpaint has invested years of development and engineering to be ready for the future.

To create something completely new  happens very seldom in the coatings industry. And yet Steelpaint has developed the next generation of single-pack moisture cure coatings based on polyurethane, without any Isocyanates and with very low VOC-levels.

The Stelcatec line of products truly represents a ground breaking innovation in corrosion protection coatings. With this achievement the continuing existence of MCPU-technology is secured for the future. Apart from the fact that there are no Isocyanates it is important to know that all the “normal” advantages of the technology (mentioned above) are still there in the Stelcatec line. Due to its low VOC and lack of isocyanates the material is not even labelled as  dangerous goods.

As an extra bonus the total Stelcatec system (primer, intermediate and topcoat) can be spray-applied wet-in-wet within 45 minutes. Even under “out of spec” weather conditions.

These capabilities may very well revolutionize coating maintenance in various industries in the years to come.

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