Polyurethane, Polyurea and Hybrid Lining Technology

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Polyurethane, Polyurea and Hybrid Lining
Technology

• Presented by Dudley Primeaux, PCS
• VersaFlex Incorporated

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Introduction

• This webinar reviews application of polyurea,
  polyurethane, or polyurea/polyurethane hybrid
  thick film coatings to steel or concrete surfaces
  using plural-component spray application

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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

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SSPC-Paint 45

• A coating standard that contains minimum
  performance requirements for polyurea and
  polyurea/polyurethane hybrid coatings

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SSPC-Paint 45 Coating Types

• 2 types defined
• Type 1
• Polyurea
• 1a, Fast Cure
• Dry in less than 2 minutes
• 1b, Moderate Cure
• Dry time is 2 minutes 30 minutes
• Type 2
• Polyurea/Polyurethane Hybrid
• 2a, Fast Cure
• Dry in less than 2 minutes
• 2b, Moderate Cure
• Dry time is 2 minutes-30 minutes

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Polyurea

• A coating material which is the reaction product
  of an isocyanate and a polyamine.

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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

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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

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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

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SSPC Paint 39
Exposure Test Performance Level Exposure Time Color Retention Per ASTM D2244 Maximum Gloss Reduction From Original Reading Per ASTM D523
ASTM D4587 Level 1A 500 h 2.0 ?E 20
ASTM D4587 Level 2A 1000 h 3.0 ?E 30
ASTM D4587 Level 3A 2000 h 3.0 ?E 40
ASTM D1014 Level 1N 12 mo 2.0 ?E 35
ASTM D1014 Level 2N 24 mo 3.0 ?E 50
From Table 1 Summary of Performance Testing
Results to be Reported
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Polyurethane

• A coating binder material formed by the reaction
  of an isocyanate with hydroxyl-containing
  substances (polyols) to produce an organic
  polymer compound known as a urethane

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Types of Polyurethanes

• Conventional 2-part (thin film)
• Moisture cure polyurethane single component
• 100 solids/elastomeric (thick film)

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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

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SSPC Paint No. 36
Accelerated UV-A Testing
Performance Level Hours to Noticeable Change 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
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SSPC Paint No. 36
Exposure Test Performance Level Exposure Time Color Change ASTM D2244 Maximum Gloss Reduction ASTM D523
Accelerated Weathering ASTM D4587 Level 1 500 h Less than 2.0 ?E 25 from original reading
Accelerated Weathering ASTM D4587 Level 2 1000 h Less than 2.0 ?E 25 from original reading
Accelerated Weathering ASTM D4587 Level 3 2000 h Less than 2.0 ?E 25 from original reading
South Florida Weathering ASTM D1014 Level 1 12 mo Less than 2.0 ?E 35 from original reading
South Florida Weathering ASTM D1014 Level 2 24 mo Less than 2.0 ?E 35 from original reading
South Florida Weathering ASTM D1014 Level 3 48 mo Less than 2.0 ?E 35 from original reading
From Table 2 Summary of Performance Testing
Results to be Reported
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Conventional 2-Part Polyurethane

• Excellent color and gloss retention
• Good chemical/solvent resistance
• Good hardness/abrasion resistance

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Characteristics of Moisture-Cured Urethane
Coatings

• Moisture-Cured Urethane (MCU) Coatings
• Advantages
• Limitations

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Polyurethane Advantages

• Turn Around Time
• 100 Solid
• Can Have Some Limited Ability to Apply During
  Winter Months
• Unique Self-Inspecting Property

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Hybrid

• A blend of polyurea and polyurethane

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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

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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

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Service Environments

• SSPC-Paint 45 coatings are suitable for
  application in the following SSPC environmental
  zones
• 1A (Interior, normally dry)
• 1B (Exterior, normally dry)
• 2A (Frequently wet by fresh water, excluding
  immersion)
• 2B (Frequently wet by salt water, excluding
  immersion)
• 2C (Fresh water immersion)
• 2D (Salt water immersion)

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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 D4417, 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

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Surface Preparation of Concrete

• Verify that the concrete substrate is sound and
  solid
• ASTM C805, 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

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Rebound Hammer and ICRI 310.2 CSP replicate
plaques

• ASTM D7682, Standard Test Method for Replication
  and Measurement of Concrete Surface Profiles
  Using Replica Putty

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Coating Material Receipt

• Check that coatings delivered
• Are in original, unopened containers with labels
  intact
• That containers are not damaged
• Have readily accessible PDSs and SDSs
• 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
  manufacturers recommendations
• Are within applicable shelf life

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Mixing

• Mix each individual component of the coating
  system in accordance with manufacturers
  instructions
• Verify proper mix ratio of coating components
  prior to placement into plural component equipment

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Mixing
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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

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Pre-Application Checks (Contd)

• 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 manufacturers 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

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Application Equipment

• Coating are applied by high-pressure or
  low-pressure 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

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Mixing at the Gun
Air purge gun
Mechanical purge gun
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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 D4541,
  Method D or E
• Average of 3 pulls
• For concrete test in accordance of ASTM D7234
• Average of 3 pulls

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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

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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

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Coating Continuity

• Inspect coating for a cured film that is
  continuous and pinhole free
• NACE SP0188, Discontinuity (Holiday) Testing of
  New Protective Coatings on Conductive Substrates
• ASTM D4787, Standard Practice for Continuity
  Verification of Liquid or Sheet Linings Applied
  to Concrete Substrates

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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

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Questions?