Polyurethane, Polyurea and Hybrid Lining Technology

Presented by: Dudley Primeaux, PCSVersaFlex Incorporated

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

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

SSPC-Paint 45• A coating standard that contains

minimum performance requirements for polyurea and polyurea/polyurethane hybrid coatings

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

Polyurea• A coating material which is the

reaction product of an isocyanate and a polyamine.

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

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

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

SSPC Paint 39Exposure 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

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

Types of Polyurethanes• Conventional 2-part (thin film)• Moisture cure polyurethane single

component• 100% solids/elastomeric (thick film)

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

SSPC Paint No. 36

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

Accelerated UV-A Testing

From Table 1: Time Corresponding to Each Performance Level

SSPC Paint No. 36Exposure Test Performance Level Exposure

TimeColor Change ASTM D2244

Maximum Gloss Reduction ASTM D523

Accelerated Weathering ASTM D4587

Level 1 500 h Less than 2.0 ΔE 25% from original reading

Accelerated Weathering ASTM D4587

Level 2 1000 h Less than 2.0 ΔE 25% from original reading

Accelerated Weathering ASTM D4587

Level 3 2000 h Less than 2.0 ΔE 25% from original reading

South Florida Weathering ASTM D1014

Level 1 12 mo Less than 2.0 ΔE 35% from original reading

South Florida Weathering ASTM D1014

Level 2 24 mo Less than 2.0 ΔE 35% from original reading

South Florida Weathering ASTM D1014

Level 3 48 mo Less than 2.0 ΔE 35% from original reading

From Table 2: Summary of Performance Testing Results to be Reported

Conventional 2-Part Polyurethane

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

Characteristics of Moisture-Cured Urethane Coatings• Moisture-Cured Urethane (MCU)

Coatings– Advantages– Limitations

Polyurethane Advantages• Turn Around Time• 100% Solid• Can Have Some Limited Ability to

Apply During Winter Months• Unique “Self-Inspecting” Property

Hybrid• A blend of polyurea and

polyurethane

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

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

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)

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

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

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

Coating Material Receipt• Check that coatings delivered:

– Are in original, unopened containers with labels intact

– That containers are not damaged– Have readily accessible PDS’s and SDS’s– 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 manufacturer’s recommendations

– Are within applicable shelf life

Mixing• Mix each individual component of

the coating system in accordance with manufacturer’s instructions

• Verify proper mix ratio of coating components prior to placement into plural component equipment

Mixing

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

Pre-Application Checks (Cont’d)• 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 manufacturer’s 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

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

Mixing at the Gun

Air purge gun Mechanical purge gun

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

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

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

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

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

Questions?