Polyurethane, Polyurea and Hybrid Lining Technology
Presented by: Dudley Primeaux, PCSVersaFlex Incorporated
Introduction• This webinar reviews
application of polyurea, polyurethane, or polyurea/polyurethane hybrid thick film coatings to steel or concrete surfaces using plural-component spray application
SSPC Standards• SSPC-Paint 45, Two-Component,
Thick-Film Polyurea and Polyurea/Polyurethane Hybrid Coatings, Performance-Based– Expected to be released by December
2013
• SSPC-PA 14, Application of Thick Film Polyurea and Polyurethane Coatings to Concrete and Steel Using Plural-Component Equipment
SSPC-Paint 45• A coating standard that contains
minimum performance requirements for polyurea and polyurea/polyurethane hybrid coatings
SSPC-Paint 45 Coating Types• 2 types defined
– Type 1• Polyurea
– 1a, Fast Cure» Dry in less than 2 minutes
– 1b, Moderate Cure» Dry time is 2 minutes – 30 minutes
– Type 2• Polyurea/Polyurethane Hybrid
– 2a, Fast Cure» Dry in less than 2 minutes
– 2b, Moderate Cure» Dry time is 2 minutes-30 minutes
Polyurea• A coating material which is the
reaction product of an isocyanate and a polyamine.
Polyureas• Isocyanate Component can be
aromatic or aliphatic• Resin / Polyamine Component can
be aromatic or aliphatic– Aromatic based systems will yellow or
fade but not crack– Aliphatic based systems have excellent
weatherability
Polyurea Properties• Good elongation and flexibility• Excellent chemical/solvent
resistance• Can be applied in low temperatures• Good thermal shock resistance• Turn Around Time• 100% Solids
Polyurea Standard• SSPC Paint No. 39, Two-Component
Aliphatic Polyurea Topcoat Fast or Moderate Drying, Performance Based– Type 1: Fast Drying
• Less than 30 minutes
– Type 2: Moderate Drying• 30 minutes to 2 hours
SSPC Paint 39Exposure Test
Performance Level
Exposure Time
Color Retention Per ASTM D2244
Maximum Gloss Reduction From Original Reading Per ASTM D523
ASTM D4587 Level 1A 500 h ≤ 2.0 ∆E 20%
ASTM D4587 Level 2A 1000 h ≤ 3.0 ∆E 30%
ASTM D4587 Level 3A 2000 h ≤ 3.0 ∆E 40%
ASTM D1014 Level 1N 12 mo ≤ 2.0 ∆E 35%
ASTM D1014 Level 2N 24 mo ≤ 3.0 ∆E 50%
From Table 1: Summary of Performance Testing Results to be Reported
Polyurethane• A coating binder material formed by
the reaction of an isocyanate with hydroxyl-containing substances (polyols) to produce an organic polymer compound known as a urethane
Types of Polyurethanes• Conventional 2-part (thin film)• Moisture cure polyurethane single
component• 100% solids/elastomeric (thick film)
Conventional 2-Part Polyurethane• Waterborne formulations
– Use water dispersible polyisocyanate
• Slower cure• Longer potlife• Typically aliphatic
– SSPC Paint Specification No. 36• Two Component Weatherable Aliphatic
Polyurethane Topcoat, Performance-Based
SSPC Paint No. 36
Performance Level
Hours to Noticeable Change
Months to Noticeable Change
Level 1 500 to 999 12 to 23
Level 2 1000 to 1999 24 to 47
Level 3 2000 or more 48 or more
Accelerated UV-A Testing
From Table 1: Time Corresponding to Each Performance Level
SSPC Paint No. 36Exposure Test Performance Level Exposure
TimeColor Change ASTM D2244
Maximum Gloss Reduction ASTM D523
Accelerated Weathering ASTM D4587
Level 1 500 h Less than 2.0 ΔE 25% from original reading
Accelerated Weathering ASTM D4587
Level 2 1000 h Less than 2.0 ΔE 25% from original reading
Accelerated Weathering ASTM D4587
Level 3 2000 h Less than 2.0 ΔE 25% from original reading
South Florida Weathering ASTM D1014
Level 1 12 mo Less than 2.0 ΔE 35% from original reading
South Florida Weathering ASTM D1014
Level 2 24 mo Less than 2.0 ΔE 35% from original reading
South Florida Weathering ASTM D1014
Level 3 48 mo Less than 2.0 ΔE 35% from original reading
From Table 2: Summary of Performance Testing Results to be Reported
Conventional 2-Part Polyurethane
• Excellent color and gloss retention• Good chemical/solvent resistance• Good hardness/abrasion resistance
Characteristics of Moisture-Cured Urethane Coatings• Moisture-Cured Urethane (MCU)
Coatings– Advantages– Limitations
Polyurethane Advantages• Turn Around Time• 100% Solid• Can Have Some Limited Ability to
Apply During Winter Months• Unique “Self-Inspecting” Property
Hybrid• A blend of polyurea and
polyurethane
100% Solids/Elastomeric• Typically aromatic• Fast cure• High build, up to 100+ mils (2.5+
mm)• Good elongation and flexibility• Excellent chemical and solvent
resistance• Can be applied in low temperatures• Low VOC
Thick Film• Greater than 20 mils (500 µm) dry
film thickness• Shown here is a wet film gage used in some Moderate Cure systems
• Fast Cure systems would require the use of either a Type 1 magnetic or Type 2 electronic gage, or an ultrasonic gage
Service Environments• SSPC-Paint 45 coatings are suitable for
application in the following SSPC environmental zones:– 1A (Interior, normally dry)– 1B (Exterior, normally dry)– 2A (Frequently wet by fresh water,
excluding immersion)– 2B (Frequently wet by salt water,
excluding immersion)– 2C (Fresh water immersion)– 2D (Salt water immersion)
Surface Preparation of Steel• Removal of Visible Contaminants
– SSPC-SP 1, Solvent Cleaning• Removal of Non-Visible Contaminants
– SSPC Guide 15, Field Methods for Retrieval and Analysis of Soluble Salts on Steel and Other Nonporous Substrates
• Minimum Surface Profile of 3 mils (76 µm)– ASTM D4417, Standard Test Methods for Field
Measurement of Surface Profile of Blast Cleaned Steel
– Method B– SSPC-PA 17, Procedure for Determining
Conformance to Steel Profile/Surface Roughness/Peak Count Requirements
Surface Preparation of Concrete• Verify that the concrete substrate is sound
and solid– ASTM C805, Standard Test Method for
Rebound Number of Hardened Concrete• Repair surface defects such as: bugholes,
voids and cracks• Clean the surface so it is free of dust, dirt,
grease and oils, contaminants, laitance, and loosely adhering concrete (SSPC-SP 13)
• Create a surface roughness within ICRI 310.2, CSP range of 2-6
Rebound Hammer and ICRI 310.2 CSP replicate plaques
• ASTM D7682, Standard Test Method for Replication and Measurement of Concrete Surface Profiles Using Replica Putty
Coating Material Receipt• Check that coatings delivered:
– Are in original, unopened containers with labels intact
– That containers are not damaged– Have readily accessible PDS’s and SDS’s– Each container is marked, showing: coating
identification, date of manufacturer, batch number, and basic chemical composition
– Coatings are stored in accordance with applicable federal, state and local safety regulations
– Coatings are stored in accordance with manufacturer’s recommendations
– Are within applicable shelf life
Mixing• Mix each individual component of
the coating system in accordance with manufacturer’s instructions
• Verify proper mix ratio of coating components prior to placement into plural component equipment
Mixing
Pre- Application Checks• Prior to application of the coating
check:– Ambient conditions
• Coating is not to be applied in wind, snow, fog, mist or rain.
• Coating is not to be applied to wet or damp substrates
– Temperature• The surface temperature, temperature of
the coating and ambient air temperature must be within coating manufacturers requirements
Pre-Application Checks (Cont’d)• Humidity
– Coating shall not be applied when the surface temperature is less than 5 degrees Fahrenheit (3 degrees Centigrade) above the dew point
• Concrete Substrate Moisture– The moisture level of the concrete shall
comply with the coating manufacturer’s requirements as determined by the measurement method specified on the PDS
• Steel Substrate Moisture– Apply coating to dry substrates that are free
of any water in seams, fasteners or joints
Application Equipment• Coating are applied by high-pressure or
low-pressure plural component spray equipment
• Equipment is capable proportioning and heating the fluid
• The spray gun is capable of mix and dispense of the thick film coating to the desired DFT and pattern specified on PDS– DFT can be achieved in 1-3 overlapping
passes
Mixing at the Gun
Air purge gun Mechanical purge gun
Test Area• Prior to spraying project area, create
a test area– ~11 square feet (1 square meter) in
size– Test adhesion
• For steel test in accordance of ASTM D4541, Method D or E
– Average of 3 pulls
• For concrete test in accordance of ASTM D7234
– Average of 3 pulls
Application• Primer
– Applied in accordance with PDS– Applied in a visually continuous film
with overlapping at the edges of the spray pattern
• Topcoat– Applied in accordance with PDS– Not applied until primer has cured– Applied within recoat window of primer
Coating Thickness• The coating thickness is verified by:
– Steel: SSPC-PA 2, Procedure for Determining Conformance to Dry Coating Thickness Requirements
- Type 1 (magnetic) or Type 2 (electronic)
– Concrete: SSPC-PA 9, Measurement of Dry Coating Thickness on Cementitious Substrates Using Ultrasonic Gages
Coating Continuity• Inspect coating for a cured film that
is continuous and pinhole free– NACE SP0188, Discontinuity (Holiday)
Testing of New Protective Coatings on Conductive Substrates
– ASTM D4787, Standard Practice for Continuity Verification of Liquid or Sheet Linings Applied to Concrete Substrates
Summary• By following appropriate test
methods and good practices, polyurea, polyurethane and hybrid coatings can provide excellent corrosion protection for concrete and steel substrates
• This protection includes a variety of interior and exterior coating work, as well as immersion lining application areas
Questions?