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)

Application Equipment

Application Equipment

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

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

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?