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 (-NH 2 ) 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)

Application Equipment

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

Application

Polyurethane Systems Conventional polyurethane for steel structures (exterior tank, bridges) Surface preparation: SP 10, profile 2-3 mils Application: Zinc 3 – 5 mils DFT Epoxy 4 – 6 mils DFT Aliphatic 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 2 – 3 mils DFT/coat 2 coats waterborne urethane 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 13 – 15 mils DFT

Polyurethane Systems Concrete tank lining Surface preparation: ASTM D4259/ ICRI 03732, CSP 5 Application: Epoxy 5 – 7 mils DFT 100% solids elastomeric 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 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 3 – 5 mils DFT 100% solids aromatic 60 – 100 mils DFT

Polyurea Systems Steel structures (exterior tank, bridges) Surface preparation: SP 10, profile 2-3 mils Application: Zinc 3 – 4 mils DFT Aliphatic 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 3 – 5 mils DFT 100% solids elastomeric polyurea 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

Summary of Key Points Polyurethanes Thin film conventional and waterborne Single component moisture cure 100% solids thick film Polyureas 100% solids thick film No moisture sensitivity Thin film polyaspartics

Summary of Key Points (cont.) Blast cleaning generally required Plural component application for 100% solids polyurethane/polyurea May allow for low temperature applications Minimize down time

Advances in Polyurethane and Polyurea Technology Questions?