Frequently Asked Questions
What Is The Recommended Surface Prep Standards For FEVE Coatings On Mild Steel For A Newbuild Vessel?
Surface prep is no different than is required in conventional systems
Any Automotive Structural Components Being Tested? Any Cyclic Corrosion Testing Evaluations Done On This Coating?
We have not tested FEVE resins for automotive structural components. We are doing corrosion testing.
If the previous coating was not high in silicone content, then power washing to remove dirt and any mold is best. If there is silicone content, sand blasting may be needed to rough up the surface to provide for optimal adhesion. It is never recommended to coat over rust. Rust on the surface will prevent proper adhesion allowing an avenue for moisture intrusion. This will propagate the rust formation.
Aluminum is protected from corrosion in large part by the thin oxide layer that forms on it or it is pretreated. However, pitting corrosion and localized corrosion can occur (typically seen in alloys of aluminum). In order to protect against this it is important to use a system with good adhesion to the aluminum substrate. Typically this will require the use of some type of primer or pretreatment. The finish coat should have excellent resistance to UV degradation and water. In extreme situations anti-corrosion additives may be used.
The ultra-weatherability of LUMIFLON resins is the reason for their popularity in many exterior coating applications. This question of why they work so well is frequent among our potential customers. The outstanding weatherability of FEVE-based coatings is attributable to the high bond energy of the carbon-fluorine bond. These carbon-flourine bonds have the capability to absorb much greater amounts of UV energy and will keep this energy from affecting the weaker bonds/ linkages in the LUMIFLON polymer structure. This means that it is difficult for the UV energy to generate free radicals in FEVE resins, the method by which degradation of coatings by UV energy is propagated.
Knowing this, you can see why the presence of the fluorine bonds needs to be equally spread out along the polymer backbone so as to insure protection of the entire backbone. The alternating structure created in all of the LUMIFLON resins – every fluoroethylene monomer segment sandwiched between the vinyl ether monomer segments – makes the achievement of a 30-60 year coating attainable.
The laboratory testing of this property is quite extensive. For the accelerated weathering in the laboratory, we utilize the QUV Weatherometer and the Xenon Arc Weatherometer. For the long term outside exposure, we send test panels to both South Florida testing sites and to Arizona testing sites for the EMMAQUA exposure (EMMAQUA stands for “Equatorial Mount with Mirrors for Acceleration with Water”). We also monitor actual LUMIFLON coating applications on structures as they age.
This is a question that is often asked by potential customers for LUMIFLON resins. They wonder how much protection is provided by a LUMIFLON resin for the other ingredients in the formulation – namely colored pigments and other non-fluorinated resins. In my experience, the protection that a LUMIFLON resin will give to other ingredients is hard to measure. I have noticed that organic pigments that are sensitive to UV degradation also need UV absorbers in the formulation to protect them from losing their color. Whether or not these UV absorbers are given additional protection from degradation by the presence of a LUMIFLON resin has yet to be determined. As far as protection for non-fluorinated resins, there seems to be some credence to the proclamation that these resins will perform better in the presence of LUMIFLON resins. I have tested formulations containing only 20% of the total binder as a LUMIFLON resin and have seen dramatic differences in both gloss retention and also the condition of the paint film after extensive UV exposure. However, it is important to understand that LUMIFLON resins cannot prevent UV radiation from penetrating through a film that is composed of LUMIFLON resins. UV absorbers are necessary to stop this penetration in clearcoat formulations. Otherwise, the UV radiation can deteriorate the substrate beneath the clearcoat and cause delamination of the coating.
At What Wavelength Does The FEVE Resin Start To Degrade At? Or, What Wavelengths Are Critical To Protect From?
FEVE resins exhibit little to no absorption in the UVA and UVB range. The key to formulating durable coatings with FEVE resins is to protect the components that are sensitive to these wavelength ranges, i.e. organic pigments, titanium dioxide, certain resin chemistries. It is recommended that triazine type UV absorbers and hindered amine light stabilizers (HALS) be used in coatings with FEVE resins in order to achieve maximum durability.
Yes. Coatings formulated with FEVE resins show improved resistance to sulfuric acid.
Yes. QUV-B, Xenon Arc, and South Florida have been performed. The results showed that FEVE based powder coatings had greater than 95% gloss retention after 3500hrs QUV-B, greater than 99% gloss retention after 6000hrs Xenon Arc, and greater than 60% gloss retention after 10 years South Florida.
The UV resistance of FEVE resins is not dependent on crosslinking.
These coatings have been applied to structures in all types of climate conditions, some more severe than the Northeast USA.
FEVE is the most UV durable resin available. It is best to use this in the topcoat to get optimal benefits.
FEVE based coatings are currently being used on concrete substrates submerged in water.
Yes. Proper preparation of the substrate is critical for long term performance.
Yes. We tested Sulfuric Acid at 50% in a 1 hour spot test. We also tested 10% Sulfuric Acid in a 30 day immersion test. We saw passing results in both tests.
Is There A Standard ASTM Test Method For Real Life Exposure To Salt Water That May Be Preferred Over The B117 Test Method?
ASTM G85 is another salt fog test called Prohesion. A modified version of this test cycles between salt fog exposure and QUV exposure. Some have suggested that prohesion yields results more comparable to real world exposure.
Have The Corrosion Protections Of The FEVE Coatings Been Measured Without A Primer (i.e. Direct To Metal)?
Yes. This work is underway currently.