530 likes | 821 Views
Water- Based, Weatherable Coatings Presented by: Bob Parker, AGC Chemicals Americas, Inc. Learning Outcomes. At the end of this webinar, you will be able to: Define fluoroethylene vinyl ether (FEVE) resins Recognize when FEVE resins are water-based or solvent-based
E N D
Water- Based, Weatherable CoatingsPresentedby: Bob Parker, AGC Chemicals Americas, Inc.
Learning Outcomes • At the end of this webinar, you will be able to: • Define fluoroethylene vinyl ether (FEVE) resins • Recognize when FEVE resins are water-based or solvent-based • Understand why FEVE resins have exceptional weatherability
Fluoroethylene Vinyl Ether (FEVE) Resins A hybrid fluoropolymer resin with the ability to be used in standard coating formulations like any other conventional coating resin
FEVEResins Unite the characteristics of fluoropolymers and urethanes The polymer structure and the strength of the chemical bonds yield weatherable coatings with excellent corrosion resistance
FluoroethyleneVinyl Ether (FEVE) Resins FLUORINATED SEGMENTS: Weatherability, durability, chemical resistance VINYL ETHER SEGMENTS: Gloss, solubility, crosslinking
FEVEResins • FEVE resins are being used for: • Architectural Coatings for commercial buildings • Industrial Maintenance Coatings for water towers, bridges, and assorted metal and concrete structures • Aerospace coatings • Applications in Marine environments
Advantages of FEVE Resins • The chemical bond between the carbon atoms and fluorine atoms is too strong to be broken by sunlight • Polymer is not degraded by ultraviolet radiation from sunlight • Alternating structure of the resin increases the strength of the other chemical bonds in the polymer, which protects the entire coating against degradation
Types of FEVE Resins • Solvent Soluble Resins • Uses organic solvents for viscosity reduction • Predominantly cured with isocyanates • Water-Based Emulsions • Uses vinyl ether macromonomers containing polyoxyethylene units to create stable emulsions • Water-Based Dispersion • Lower molecular weight dispersion
Weatherability of FEVE Based Coatings • Accelerated and natural weathering tests show fluorourethane coatings have exceptional weatherability • QUV-A Test (ASTM D4587) • EMMAQUA Test (ASTM G90) • South Florida Test • Electrochemical Impedance Spectroscopy (EIS)
QUV-A Test (ASTM D4587) Exposes coated steel panels to a ultraviolet light at a constant wavelength of 340nm Gloss retention is measured for 5,000 hours
EMMAQUA Test (ASTM G90) Uses mirrors to focus natural light onto coated panels, exposing the panel to all the wavelengths found in natural light Panels are sprayed periodically with water to simulate rain Results reported in units of energy exposure per unit area (MJ/m2) and percentage of gloss retention
EMMAQUA Test (ASTM G90) 1,000 MJ/m2 corresponds to 10yrs of exposure FEVE showed excellent gloss retention after 2800 MJ/m2
South Florida Test • Outdoor coated panel testing farm • Harsh environment consisting of: • High wavelengths of ultraviolet light • Marine atmosphere • Heavy rain • FEVE coated panels tested for 10yrs • FEVE coatings retained 70% gloss
Electrochemical Impedance Spectroscopy (EIS) Method to measure corrosion Alternating current is sent between a 3% saline solution and a coated metal panel Change in impedance at a constant frequency of 1kHz is measured The smaller the change in impedance, the better the corrosion protection
Electrochemical Impedance Spectroscopy (EIS) Results indicate that the FEVE coating offers better corrosion protection than a polyurethane, chlorinated rubber or alkyd
Case History • Tokiwa Bridge- Japan • Painted in 1986 • Coating System: • Epoxy/Epoxy/FEVE/FEVE • Surface Preparation : SSPC SP 2/SP 3
Case History • Suruga Bay Marine Test Station (Offshore) • Painted in 1994 • Coating System: • Zinc Rich Primer/Epoxy Midcoat/Acrylic Urethane Topcoat • Zinc Rich Primer/Epoxy Midcoat/Fluoroethane Topcoat • Thickness of Coatings: • Primer = 75 microns (3 mils) • Midcoat = 150 microns (6 mils) • Topcoat = 25 microns (1 mil)
Water-Based Emulsions • Possess higher molecular weight • Permits one component coatings to be formulated • OH functionality • Allows formulation of two component coatings • Limitations • Inferior performance compared to solvent counterparts
Performance Properties of FEVE Dispersion • Performance properties were conducted on 4 coatings: • Solvent soluble FEVE coating • 2 component water-based emulsion FEVE coating • 1 component water-based emulsion FEVE coating • Water-based dispersion FEVE coating
Performance Properties of FEVE Dispersion Coatings were applied to chromate treated steel panels Panels cured 14 days @ ambient conditions
Performance Properties of FEVE Dispersion • The following performance properties were tested: • Solvent Resistance (ASTM D5402) • Gloss Retention (ASTM D523) • Coating Hardness (ASTM D4366 and D2794) • Adhesion (ASTM D3359) • Water Resistance
ASTM D5402 A solvent rub technique for assessing the solvent resistance of an organic coating that chemically changes during the curing process
ASTM D523 Covers the measurement of the specular gloss of nonmetallic specimens for glossmeter geometries of 60, 20, and 85°
ISO 1522 Covers the use of pendulum damping testers in the determination of hardness of organic coatings that have been applied to acceptably plane rigid surfaces, such as a metal or glass panel
ASTM D2794 Covers a procedure for rapidly deforming by impact a coating film and its substrate and for evaluating the effect of such deformation
ASTM D3359 Covers procedures for assessing the adhesion of coating films to metallic substrates by applying and removing pressure-sensitive tape over cuts made in the film
Film Properties * Crosshatch Adhesion Test after 24 hour warm water (40° C) soak
Summary Due to the unique chemical structure of FEVE resins they are an excellent choice when corrosion resistance is needed. Testing has indicated that a water-based FEVE dispersion resin can withstand extreme weather and maintain performance properties when required to perform under degrading conditions
Acknowledgements: Naoko Sumi Isao Kimura Masakazu Ataku Takashige Maekawa
Conclusion This concludes our webinar for today. Please join us for our next webinar, December 8th at 1 pm EST on Developing a Maintenance Painting Program for a Petrochemical Plant