Advances in Polyurethane and Polyurea Technology

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Advances in Polyurethane and Polyurea Technology

• Presented by
• Jayson L. Helsel, P.E.
• KTA-Tator, Inc.

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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

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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)

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Basic Chemistry/Properties

• Polyurethanes
• Polyureas
• Hybrid coatings

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Polyurethanes

• Polyurethanes are formed by the reaction between
  a polyisocyanate and hydroxyl (-OH) containing
  resin blend

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Polyurethanes

• Disocyanate can be aromatic or aliphatic
• Wide variety of formulations

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Polyurethanes

• Conventional 2-part (thin film)
• Waterborne formulations
• Moisture cure polyurethane single component
• End product can be polyurethane or polyurea
  chemistry
• 100 Solids/Elastomeric

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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

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SSPC Paint No. 36

• Weathering levels for color and gloss
  (accelerated or Florida exposure)
• Level 1 (lt1000 hrs or lt24 months)
• Level 2 (lt2000 hrs or lt 48 months)
• Level 3 (gt2000 hrs or gt 48 months)
• Color max 2.0 ?E, Gloss max loss 30

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Polyurethanes

• Thin-film polyurethanes properties
• Typically aliphatic
• Slower cure
• Excellent color and gloss retention
• Good chemical/solvent resistance
• Good hardness/abrasion resistance

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Polyurethanes

• 100 Solids/Elastomeric
• Typically aromatic
• Fast cure
• Hi build, up to 100 mils

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Polyurethanes

• 100 solids polyurethane properties
• Elongation/flexibility
• Excellent chemical/solvent resistance
• Moisture sensitive application
• Can be applied in low temperatures (below
  freezing)
• Low VOC

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Polyureas

• Formed by the reaction between an isocyanate
  component and an amine-terminated (-NH2) resin
  blend

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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

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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

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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

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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

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Polyureas

• Fast cure
• Moderate cure
• Hybrid systems
• SSPC Paint Specification No. 39
• Two-Component Aliphatic Polyurea Topcoat Fast or
  Moderate Drying, Performance Based

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SSPC Paint No. 39

• Type 1 Fast Drying (less than 30 minutes)
• Type 2 Moderate Drying (30 minutes to 2 hours)
• Weathering levels

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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

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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

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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

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Surface Preparation

• Steel
• Abrasive blast cleaning to SSPC-SP 10, Near White
• Angular surface profile

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Surface Preparation

• Concrete
• Abrasive blast cleaning
• Profile/roughening required
• Specialized primer may be necessary
• Check moisture content

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Application Equipment

• Thin film polyurethanes and polyureas
  (polyaspartics)
• Conventional or airless spray
• 100 solids polyurethanes and polyureas
• Plural component spray

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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

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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

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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)

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Application Equipment
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Application Equipment
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Application Equipment
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Polyurethane Applications

• Roof coatings
• Pipe
• Tank interior/exterior
• Truck bed liners
• Railcars
• Parking decks
• Anti-graffiti coatings
• Caulk/joint/sealant materials

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Polyurea Applications

• Roof coatings
• Pipe
• Tank linings
• Truck bed liners
• Railcars
• Parking decks
• Caulk/joint/sealant materials

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Polyurethane Systems

• Conventional polyurethane for steel structures
  (exterior tank, bridges)
• Surface preparation SP 10, profile 2-3 mils
• Application
• Zinc primer _at_ 3 5 mils DFT
• Epoxy intermediate _at_ 4 6 mils DFT
• Aliphatic polyurethane _at_ 3 5 mils DFT

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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 _at_ 2 3 mils
  DFT/coat
• 2 coats waterborne urethane finish _at_ 2 3 mils
  DFT/coat

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Polyurethane Systems

• Waterborne polyurethane properties
• Tensile strength 5950 psi
• Elongation 150
• Taber abrasion lt45 mg loss/1000 cycles
• Graffiti resistance Level 3, ASTM D6578

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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

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Polyurethane Systems

• Steel pipe (exterior) coating
• Surface preparation SP 10, profile 2.5 mils
  minimum
• Application
• 100 solids polyurethane _at_ 13 15 mils DFT

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Polyurethane Systems

• Concrete tank lining
• Surface preparation ASTM D4259/ ICRI 03732, CSP
  5
• Application
• Epoxy primer _at_ 5 7 mils DFT
• 100 solids elastomeric polyurethane _at_ 60 80
  mils DFT

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Polyurethane Systems

• Elastomeric polyurethane properties
• Shore A hardness 60
• Adhesion to concrete 350 psi
• Elongation 400
• Tear strength 150 psi
• Tensile strength 900 psi

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Polyurethane Systems

• Elastomeric polyurethane chemical immersion
• Acetic acid, 10
• Hyrdochloric acid, 10
• Methanol
• Nitric acid, 10
• Phosphoric acid, 10
• Sulfuric acid, 30

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Polyurea Systems

• Steel tank lining
• Surface preparation SP 10, profile 3 mils
• Application 100 solids aromatic elastomeric
  polyurea _at_ 60 80 mils DFT

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Polyurea Systems

• Elastomeric polyurea properties
• Shore D hardness 50
• Elongation 250
• Tensile strength 2125 psi
• Tear strength 390 psi

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Polyurea Systems

• Elastomeric polyurea chemical immersion
• Acetic acid, 10
• Ammonium hydroxide, 20
• Hydrochloric acid, 10
• Phosphoric acid, 10
• Sulfuric acid, 10

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Polyurea Systems

• Concrete tank lining
• Surface preparation SP 13 / ICRI 03732, CSP 3-5
• Application
• Epoxy primer _at_ 3 5 mils DFT
• 100 solids aromatic polyurea _at_ 60 100 mils DFT

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Polyurea Systems

• Steel structures (exterior tank, bridges)
• Surface preparation SP 10, profile 2-3 mils
• Application
• Zinc primer _at_ 3 4 mils DFT
• Aliphatic polyaspartic _at_ 6 9 mils DFT

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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

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Polyurea Hybrid Systems

• Concrete floor coating
• Surface preparation abrasive blasting/mechanical
  roughening
• Application
• Epoxy primer _at_ 3 5 mils DFT
• 100 solids elastomeric polyurea hybrid _at_
  30 mils DFT

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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

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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

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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

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Advances in Polyurethane and Polyurea Technology

• Questions?