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Advances in Polyurethane and Polyurea Technology. Presented by: Jayson L. Helsel, P.E. KTA-Tator, Inc. Learning Objectives. Comprehension of the Advances in Polyurethane and Polyurea Technology Webinar will enable the participant to: List various types of polyurethane coatings
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Advances in Polyurethane and Polyurea Technology Presented by: Jayson L. Helsel, P.E. KTA-Tator, Inc.
Learning Objectives Comprehension of the Advances in Polyurethane and Polyurea Technology Webinar will enable the participant to: • List various types of polyurethane coatings • Describe the properties of polyurethane coatings • List various types of polyurea coatings • Describe the properties of polyurea coatings • Recognize two SSPC Performance-based Paint Standards for polyurethane and polyurea coatings
Learning Objectives (cont.) • List the basic performance differences between polyurethane and polyurea coatings • Describe the surface preparation requirements for concrete and steel • Describe the coating application equipment typically employed • List the common applications (when and where polyurethane and polyurea coatings are used)
Basic Chemistry/Properties • Polyurethanes • Polyureas • Hybrid coatings
Polyurethanes • Polyurethanes are formed by the reaction between a polyisocyanate and hydroxyl (-OH) containing resin blend
Polyurethanes • Disocyanate can be aromatic or aliphatic • Wide variety of formulations
Polyurethanes • Conventional 2-part (thin film) • Waterborne formulations • Moisture cure polyurethane single component • End product can be polyurethane or polyurea chemistry • 100% Solids/Elastomeric
Polyurethanes • Conventional 2-part (thin film) • Slower cure, longer pot life • Waterborne formulations • Use water dispersible polyisocyanates • SSPC Paint Specification No. 36 • “Two-Component Weatherable Aliphatic Polyurethane Topcoat, Performance-Based”
SSPC Paint No. 36 • Weathering levels for color and gloss (accelerated or Florida exposure) • Level 1 (<1000 hrs or <24 months) • Level 2 (<2000 hrs or < 48 months) • Level 3 (>2000 hrs or > 48 months) • Color: max 2.0 ∆E, Gloss: max loss 30
Polyurethanes • Thin-film polyurethanes properties: • Typically aliphatic • Slower cure • Excellent color and gloss retention • Good chemical/solvent resistance • Good hardness/abrasion resistance
Polyurethanes • 100% Solids/Elastomeric • Typically aromatic • Fast cure • Hi build, up to 100+ mils
Polyurethanes • 100% solids polyurethane properties: • Elongation/flexibility • Excellent chemical/solvent resistance • Moisture sensitive application • Can be applied in low temperatures (below freezing) • Low VOC
Polyureas • Formed by the reaction between an isocyanate component and an amine-terminated (-NH2) resin blend
Polyureas • Isocyanate can be aromatic or aliphatic • Aromatic resins will yellow but not crack • Aliphatic resins have excellent weatherability • Wide variety of formulations possible through particular resin blend • Typically 100% solids
Polyureas • 100% solids polyurea properties: • Elongation/flexibility • Excellent chemical/solvent resistance • Not sensitive to moisture during application • Can be applied in low temperatures (below freezing) • Thermal shock resistance • Minimize down time • Low VOC
Polyureas • Polyaspartic ester based polyureas are a newer technology • Resin blend based on aliphatic polyaspartic ester • Can have much slower reaction time • Thinner film application • Typical use is analagous to conventional polyurethanes
Polyurethane/Polyurea Hybrids • Hybrid coatings are formed by the reaction between an isocyanate component and a resin blend component • Resin blend may contain amine-terminated and/or hydroxyl-terminated polymers • Wider range for reaction time and performance properties
Polyureas • Fast cure • Moderate cure • Hybrid systems • SSPC Paint Specification No. 39 • “Two-Component Aliphatic Polyurea Topcoat Fast or Moderate Drying, Performance Based”
SSPC Paint No. 39 • Type 1: Fast Drying (less than 30 minutes) • Type 2: Moderate Drying (30 minutes to 2 hours) • Weathering levels
SSPC Paint No. 39 • Weathering Levels • Accelerated weathering levels • 1A – 500 hours, max 2.0 ∆E, 20% gloss loss • 2A – 1000 hours, max 3.0 ∆E, 30% gloss loss • 3A – 2000 hours, max 3.0 ∆E, 40% gloss loss • Outdoor weathering levels • 1N – 12 months, max 2.0 ∆E, 35% gloss loss • 2N – 24 months, max 3.0 ∆E, 50% gloss loss
SSPC Paint No. 39 • Other tests • Solvent Resistance • No visible topcoat removal (100 double rubs) • Pull-Off Adhesion • Average (3 pulls) ≥ 600 psi • Minimum 500 psi
Polyurethane vs Polyurea • Polyureas are faster cure, e.g. seconds • Polyureas not moisture sensitive • Polyurethanes cure slower but are moisture sensitive • May have fewer adhesion problems with polyurethanes
Surface Preparation • Steel • Abrasive blast cleaning to SSPC-SP 10, Near White • Angular surface profile
Surface Preparation • Concrete • Abrasive blast cleaning • Profile/roughening required • Specialized primer may be necessary • Check moisture content
Application Equipment • Thin film polyurethanes and polyureas (polyaspartics) • Conventional or airless spray • 100% solids polyurethanes and polyureas • Plural component spray
Application Equipment • Plural component spray equipment • Heats and mixes resin (part A) and curing agent (part B) components automatically in correct proportions • Paint mixture travels directly to spray gun for immediate application • Some coatings may be brush/roller applied
Application Equipment • Plural component spray equipment • Storage to deliver unmixed material • Proportioning Device • Pressure Pump • Mixing Device • Static mixer or air impingement • Delivery system (spray gun) • Flushing system
Application Equipment • Plural component application • Equipment as recommended by coating manufacturer • Requires trained/licensed applicators • Involve coating manufacturer technical representative for projects • Single application (multiple passes)
Polyurethane Applications • Roof coatings • Pipe • Tank interior/exterior • Truck bed liners • Railcars • Parking decks • Anti-graffiti coatings • Caulk/joint/sealant materials
Polyurea Applications • Roof coatings • Pipe • Tank linings • Truck bed liners • Railcars • Parking decks • Caulk/joint/sealant materials
Polyurethane Systems • Conventional polyurethane for steel structures (exterior tank, bridges) • Surface preparation: SP 10, profile 2-3 mils • Application: • Zinc primer @ 3 – 5 mils DFT • Epoxy intermediate @ 4 – 6 mils DFT • Aliphatic polyurethane @ 3 – 5 mils DFT
Polyurethane Systems • Waterborne polyurethane for steel /concrete (anti-graffiti coating) • Surface preparation: abrasive blast cleaning • Application: • Sealer/primer for concrete • 2 coats waterborne urethane primer @ 2 – 3 mils DFT/coat • 2 coats waterborne urethane finish @ 2 – 3 mils DFT/coat
Polyurethane Systems • Waterborne polyurethane properties • Tensile strength: 5950 psi • Elongation: 150% • Taber abrasion: <45 mg loss/1000 cycles • Graffiti resistance: Level 3, ASTM D6578
Polyurethane Systems • Waterborne polyurethane chemical resistance • MEK double rubs, 300+ cycles • Gasoline: no effect after 7 days • 50% NaOH: no effect after 24 hours • 10% HCl: no effect after 24 hours • Toluene: no effect after 4 hours
Polyurethane Systems • Steel pipe (exterior) coating • Surface preparation: SP 10, profile 2.5 mils minimum • Application: • 100% solids polyurethane @ 13 – 15 mils DFT
Polyurethane Systems • Concrete tank lining • Surface preparation: ASTM D4259/ ICRI 03732, CSP 5 • Application: • Epoxy primer @ 5 – 7 mils DFT • 100% solids elastomeric polyurethane @ 60 – 80 mils DFT
Polyurethane Systems • Elastomeric polyurethane properties • Shore A hardness: 60 • Adhesion to concrete: 350 psi • Elongation: 400% • Tear strength: 150 psi • Tensile strength: 900 psi
Polyurethane Systems • Elastomeric polyurethane chemical immersion • Acetic acid, 10% • Hyrdochloric acid, 10% • Methanol • Nitric acid, 10% • Phosphoric acid, 10% • Sulfuric acid, 30%
Polyurea Systems • Steel tank lining • Surface preparation: SP 10, profile 3 mils • Application: 100% solids aromatic elastomeric polyurea @ 60 – 80 mils DFT
Polyurea Systems • Elastomeric polyurea properties • Shore D hardness: 50 • Elongation: 250% • Tensile strength: 2125 psi • Tear strength: 390 psi
Polyurea Systems • Elastomeric polyurea chemical immersion: • Acetic acid, 10% • Ammonium hydroxide, 20% • Hydrochloric acid, 10% • Phosphoric acid, 10% • Sulfuric acid, 10%
Polyurea Systems • Concrete tank lining • Surface preparation: SP 13 / ICRI 03732, CSP 3-5 • Application: • Epoxy primer @ 3 – 5 mils DFT • 100% solids aromatic polyurea @ 60 – 100 mils DFT
Polyurea Systems • Steel structures (exterior tank, bridges) • Surface preparation: SP 10, profile 2-3 mils • Application: • Zinc primer @ 3 – 4 mils DFT • Aliphatic polyaspartic @ 6 – 9 mils DFT
Polyurea Systems • Polyaspartic properties • Abrasion resistance: 90 mg loss/1000 cycles • Adhesion: 825 psi • Corrosion weathering: 15 cycles ASTM D5894, Rating 10 blistering/corrosion • Freeze/thaw: 30 cycles, no adhesion loss
Polyurea Hybrid Systems • Concrete floor coating • Surface preparation: abrasive blasting/mechanical roughening • Application: • Epoxy primer @ 3 – 5 mils DFT • 100% solids elastomeric polyurea hybrid @ 30+ mils DFT
Polyurea Hybrid Systems • Elastomeric polyurea hybrid properties • Shore D hardness: 60 • Tensile strength: 2300 psi • Elongation: 100% • Tear resistance: 330 psi • Taber abrasion: 25 mg/1000 cycles