Polyurethane Polyurea and Hybrid Lining Technology Presented by
Polyurethane, Polyurea and Hybrid Lining Technology Presented by: Dudley Primeaux, PCS Versa. Flex Incorporated
Introduction • This webinar reviews application of polyurea, polyurethane, or polyurea/polyurethane hybrid thick film coatings to steel or concrete surfaces using pluralcomponent 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 – 1 a, Fast Cure » Dry in less than 2 minutes – 1 b, Moderate Cure » Dry time is 2 minutes – 30 minutes – Type 2 • Polyurea/Polyurethane Hybrid – 2 a, Fast Cure » Dry in less than 2 minutes – 2 b, 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 39 Exposure Test Performance Level Exposure Time Color Retention Per ASTM D 2244 Maximum Gloss Reduction From Original Reading Per ASTM D 523 ASTM D 4587 Level 1 A 500 h ≤ 2. 0 ∆E 20% ASTM D 4587 Level 2 A 1000 h ≤ 3. 0 ∆E 30% ASTM D 4587 Level 3 A 2000 h ≤ 3. 0 ∆E 40% ASTM D 1014 Level 1 N 12 mo ≤ 2. 0 ∆E 35% ASTM D 1014 Level 2 N 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 hydroxylcontaining 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 Accelerated UV-A Testing Performance Level Hours to 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 From Table 1: Time Corresponding to Each Performance Level
SSPC Paint No. 36 Exposure Test Performance Level Exposure Time Color Change ASTM D 2244 Maximum Gloss Reduction ASTM D 523 Accelerated Weathering ASTM D 4587 Level 1 500 h Less than 2. 0 ΔE 25% from original reading Accelerated Weathering ASTM D 4587 Level 2 1000 h Less than 2. 0 ΔE 25% from original reading Accelerated Weathering ASTM D 4587 Level 3 2000 h Less than 2. 0 ΔE 25% from original reading South Florida Weathering ASTM D 1014 Level 1 12 mo Less than 2. 0 ΔE 35% from original reading South Florida Weathering ASTM D 1014 Level 2 24 mo Less than 2. 0 ΔE 35% from original reading South Florida Weathering ASTM D 1014 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: – 1 A (Interior, normally dry) – 1 B (Exterior, normally dry) – 2 A (Frequently wet by fresh water, excluding immersion) – 2 B (Frequently wet by salt water, excluding immersion) – 2 C (Fresh water immersion) – 2 D (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 D 4417, 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 C 805, 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 D 7682, 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 lowpressure 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 D 4541, Method D or E – Average of 3 pulls • For concrete test in accordance of ASTM D 7234 – 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 SP 0188, Discontinuity (Holiday) Testing of New Protective Coatings on Conductive Substrates – ASTM D 4787, 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?
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