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– 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

FEVE Resins

• Unite the characteristics of fluoropolymers and urethanes

• The polymer structure and the strength of the chemical bonds yield weatherable coatings with excellent corrosion resistance

Fluoroethylene Vinyl Ether (FEVE) Resins

FLUORINATED SEGMENTS: Weatherability, durability, chemical resistance

VINYL ETHER SEGMENTS: Gloss, solubility, crosslinking

FEVE Resins•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

QUV-A Test (ASTM D4587)

QUV-A Test (ASTM D4587)

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

EMMAQUA Test (ASTM G90)

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

South Florida Test

South Florida Test

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

EIS

Case History• Tokiwa Bridge-

Japan• Painted in 1986• Coating System:

– Epoxy/Epoxy/FEVE/FEVE

• Surface Preparation : SSPC SP 2/SP 3

Tokiwa Bridge

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)

Suruga Bay Marine Test Station

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

Emulsion polymerization Process

↓

Preparation of FEVE Dispersion

↓

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

NCO:OH Index Solvent Resistance (100 Xylene Double-rubs)

1 PASS

0.6 PASS

0.3 FAIL

0 FAIL

Solvent Resistance

ASTM D523• Covers the measurement of the

specular gloss of nonmetallic specimens for glossmeter geometries of 60, 20, and 85°

Solvent-borne FEVE

Formula

W/B FEVE Emulsion Formula

#1

W/B FEVE Emulsion Formula

#2

W/B FEVE Dispersion

Formula

Curing Agent

(1:1 NCO:OH

Ratio)

Yes Yes No Yes

60° Gloss (ASTM D523)

90 78 78 88

Pendulum Hardness

(ISO 1522) 80 75 19 79

Direct Impact

Resistance

(ASTM D2794)

>80# 80# 20# >80#

Film Properties

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

Solvent-borne FEVE

Formula

W/B FEVE Emulsion Formula

#1

W/B FEVE Emulsion Formula

#2

W/B FEVE Dispersion

Formula

Curing Agent

(1:1 NCO:OH

Ratio)

Yes Yes No Yes

60° Gloss (ASTM D523)

90 78 78 88

Pendulum Hardness

(ISO 1522) 80 75 19 79

Direct Impact

Resistance

(ASTM D2794)

>80# 80# 20# >80#

Film Properties

ASTM D2794• Covers a procedure for rapidly

deforming by impact a coating film and its substrate and for evaluating the effect of such deformation

Solvent-borne FEVE

Formula

W/B FEVE Emulsion Formula

#1

W/B FEVE Emulsion Formula

#2

W/B FEVE Dispersion

Formula

Curing Agent

(1:1 NCO:OH

Ratio)

Yes Yes No Yes

60° Gloss (ASTM D523)

90 78 78 88

Pendulum Hardness

(ISO 1522) 80 75 19 79

Direct Impact

Resistance

(ASTM D2794)

>80# 80# 20# >80#

Film Properties

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

ASTM D3359

Solvent-borne FEVE

Formula

W/B FEVE Emulsion Formula

#1

W/B FEVE Emulsion Formula

#2

W/B FEVE Dispersion Formula

Curing Agent

(1:1 NCO:OH Ratio)

Yes Yes No Yes

Crosshatch Adhesion

(ASTM D3359)

5B 5B 0B 5B

Water resistance

Test*

5B 3B 0B 4B

Film Properties

* Crosshatch Adhesion Test after 24 hour warm water (40° C) soak

Gloss Retention of Selected FEVE Resin Systems

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 SumiIsao Kimura

Masakazu AtakuTakashige 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