1. Performance Properties of Protective Coatings
Presented by: Ahren Olson, Covestro LLC
Good morning everyone and thank you for your participation in the webinar this morning. I am going to talk today about the performance properties and attributes of protective coatings.

2. Introduction
This presentation will provide an general overview on protective coatings used in the industrial and marine industry
This presentation will be a general overview on different protective coatings used in the industrial and marine industry. I want to stress that this is a high level overview of coating technologies designed to be cover in the next 45 minutes.

3. Protective Coatings
The following coatings are used to mitigate corrosion on structures in the industrial and marine industry:
Acrylics (Waterborne)
Alkyds
Epoxies
Polyurethanes
Polyureas
Polyaspartics
Polysiloxanes
Zinc rich coatings
Today we will be covering waterborne acrylics, alkyds, epoxies, polyurethanes, polyureas, polyaspartics, polysiloxanes, and zinc rich coatings. The focus will be skewed to how this coatings perform and are used in atmospheric service.

4. Waterborne Acrylics Acrylic chemistry is very versatile
WB acrylics are thermoplastic polymers and “cure” through solvent evaporation, particle deformation, and coalescence.
Self-crosslinking products also exist and can provide additional physical properties
It is important to understand the minimum film forming temperature of the products
Acrylic chemistry is very extensive and what I mean by that is that there are a multitude of monomers that can be used to tailor the final properties of the acrylic latex. WB acrylics are thermoplastic polymers that cure through solvent evaporation, followed by particle deformation, and then coalescence of the particles into a film. WB acrylics can also be designed to have self-crosslinking properties. This can be done through a variety of mechanisms. For example the incorporation of fatty acids into polymer backbone that with auto-oxidize or incorporation of alkoxy-silane functionality that would crosslink through a condensation reaction. It is also very important to note the MFFT for the products, which would listed on product data sheets. If the WB acrylic is applied below the MFFT, poor fiolm formation will occur and the coating will have less than desirable properties.

5. Waterborne Acrylics Advantages 1K Low VOC Weatherable finish
Easily recoatable
Great for overcoating
Disadvantages
Free/thaw stability of liquid product
Lengthened drytime below 50F and at elevated humidity

6. Waterborne Acrylics
Applied to a wide variety of substrates such as metal, wood, concrete, and galvanizing.
Applied using standard spray, brush, and roll methods
A few end use applications: exterior of storage tanks, steel bridge girders, exterior of rail cars, and concrete retaining walls
WB acrylics can be applied directly or over primed metal, wood, concrete, and galvanized surfaces. This can be done by standard spray, brush, and roll methods. A few end use applications would be the exterior of storage tanks, steel bridge girders, exterior of rail cars, and concrete retaining walls.

7. Waterborne Acrylics Can be used DTM for less aggressive environments
Can also be applied over zinc rich primers in two and three coat systems for more aggressive environments

8. Waterborne Acrylics
Optimum film quality requires careful polymer (latex) design and choice of formulation additives
There are several SSPC performance based paint standards for WB acrylics

9. SSPC-Paint 23
This standard covers performance requirements for an air drying, ready-mixed, latex primer for blast cleaned steel. It is intended for use as the prime coat of a coating system consisting of one or two coats of this primer and one or two coats of a compatible topcoat

10. SSPC-Paint 24
This specification covers an air drying, ready-mixed, water-borne semi-gloss latex paint for use on metal surfaces primed with a primer conforming to SSPC-Paint 23. It is intended for use as a topcoat of a water-borne coating system consisting of two coats of primer and one or two coats of this water-borne topcoat.

11. Alkyds
Alkyds are ester based polymers and are modified by some degree with an oil or fatty acid
Short oil
Dries more rapidly, develops better gloss, hard films
OEM applications, typically sprayed or dip coated
Medium oil
Dry more slowly than short oil alkyds and are slightly softer films
OEM, Architectural, and industrial maintenance applications
Long oil
Slowest to dry and softest films
Architectural, and industrial maintenance applications
Alkyds oxidatively cure through the reaction with oxygen from the air
Alkyds are ester based polymers that are modified by some degree with an oil or a fatty acid. The length of the oil has a significant impact on the on final properties of the alkyd coating. Short oil alkyds have the fastest dry times

12. Alkyds Advantages 1K Surface tolerant Fast drying Universal primers
Low cost
Disadvantages
VOC can be high
Cannot be applied directly to zinc (primers/galv.) or concrete
Embrittlement over time
Lower film build per coat

13. Alkyds
Alkyd resin can be enhanced by incorporating a variety of synthetic resins
Phenolic alkyds
Silicone alkyds
Urethane alkyds

14. Phenolic Alkyds
Fast curing with good water/corrosion resistance, improved adhesion
Used as lacquer-resistant shop primers.
The lacquer resistant primers help to prevent the wrinkling or lifting of the primer when topcoated with solvent borne coatings with strong solvents.

15. Urethane Alkyds
Typically 15-30% of the dibasic acid is substituted by urethane modification in manufacturing process
Fast-drying, good UV resistance, improved abrasion resistance, and better alkali resistance
Wide variety of uses in both interior and exterior service
Safety colors
Structural steel
Wood flooring
The urethane modification is typically in the range of 15-30%

16. Silicone Alkyds
Best color and gloss retention within alkyd family of coatings
Typically around 30% silicone modification
Used as high quality finish coats
Structural steel
Tanks
Buildings
Silicone modified alkyds offer the best color and gloss retention within the alkyd family of coatings. Typically around 30% silicone modification is used. These coatings are used as high quality finish coats on structural steel, tankage, and buildings, marine vessels.

17. Epoxy Coatings
Most commonly used coating in the protective coating market
Reaction of an epoxy resin an amine function resin
Incredibly versatile chemistry for protective coatings
Multitude end use applications covering both immersion and atmospheric service (primers, intermediate, and finish coats)
Epoxy coatings are the most commonly used coating type in the protective coating market. These are thermosetting coatings based on the reaction of an epoxy resin and an amine component. Epoxy/amine chemistry is incredibly versatile. There are a multitude of end use applications for both immersion and atmospheric service.

18. Epoxy Coatings Advantages Excellent adhesion Chemical resistance
Corrosion resistance
Thick film possible
High temperature resistance
Disadvantages
Poor UV resistance
Poor low temperature cure
Tend to be inflexible
Limited recoat window
From a general perspective, epoxies offer great adhesion, chemical resistance, and corrosion resistance. Epoxies can be applied in very thick films depending on the application requirements. They can also be used in high temperature resistant applications.

19. Epoxy Coatings
By utilizing available variations in epoxy resins and curing agents, coatings with a variety of properties have been developed to meet a variety of end use needs
Epoxy resins
Bisphenol-A epoxy
Bisphenol-F epoxy
Novolac epoxy
Common amine resins
Polyamide
Aliphatic amines
By utilizing the available variations in both epoxy resins and curing agents, epoxy coatings can be designed for a wide range of properties to meet many different end use needs. This is far from a comprehensive list of epoxy and amine resins.

20. Bisphenol-A; Bisphenol-F; and Novolac Epoxies
Diglycidyl ether of bisphenol A (DGEBA)
General purpose resins
Diglycidyl ether of bisphenol F (DGEBF)
Lower viscosity, blended with DGEBA to prevent crystallization
Novolac resins
Excellent chemical and heat resistance
The work horse epoxy resin is the diglycidyl ether of bisphenol A commonly referred to as DGEBA.

21. Polyamide-Cured Epoxy
When compared to amine-cured epoxy, they have better:
Water resistance
Flexibility
Less tendency to amine blush
Longer pot-life

22. Polyamide-Cured Epoxy (cont’d)
Have greater amounts of solvent (VOCs), longer cure times (may require an induction period), and less chemical resistance than amine cured epoxies

23. Amine-Cured Epoxies When compared to polyamide-cured epoxies are:
More chemically resistant and faster curing
Have lower viscosities
Form tougher films
Shorter pot life
Tendency to amine blush
Less tolerant mixing ratios

24. SSPC-Paint 42
This standard contains performance requirements for a two-component epoxy polyamide/ polyamidoamine primer coating for use as a primer on blast cleaned steel surfaces

25. Polyurethanes
Formed by the reaction of a polyisocyanate and an OH-functional polyol
Most commonly used UV resistant finish coat in aggressive exposures
Two varieties
Aromatic
Aliphatic
Aromatic used as primer, intermediates, and in select immersion service
Aliphatic are for light stable finish coats

26. Aliphatic Polyurethanes
Advantages
UV resistance
Abrasion resistance
Chemical resistance
Fast drying
Cost : performance
Disadvantages
Sensitivity to moisture during cure
Out gassing when over applied
Difficult to overcoat weathered urethanes

27. Aromatic Polyurethanes
Advantages
Improved physical properties
Fast curing
Chemical resistance
Immersion service
Disadvantages
Poor UV resistance
More reactive to water can lead to greater outgassing

28. Polyurethane Coreactants
Polyethers
Better resistance to hydrolysis, but worse weathering
Used on roofs and secondary containment structures where water accumulates
Acrylics
Best color and gloss retention
Most often used polyol used for aliphatic polyurethanes
Polyesters
Best chemical and abrasion resistance

29. SSPC-Paint 36
Covers the requirements for high performance 2K, UV stable polyurethane topcoats that are suitable for varying exposures and environmental zones

30. Moisture Curing Polyurethanes
1K polyurethanes that cure through the reaction of the polyisocyanates with moisture to form a polyurea film
Used as sealers, zinc rich primers, intermediate, and finish coats
Found use in areas of high humidity
Bridges in Northwest US
Water treatment plants on sweating pipes

31. Moisture Cure Polyurethanes
Advantages
1K paint
UV resistance
Surface tolerant
Low temp cure
Fast drying
Disadvantages
Out gassing when over applied
Thinner film build that 2K aliphatic urethanes
Shelf life / can stability

32. SSPC-Paint 38
This standard contains performance requirements for a high-performance, single-component, moisture-curing UV-stable polyurethane topcoat. The coating is intended to be used as a topcoat that provides good color and gloss retention

33. SSPC-Paint 40
This specification contains performance requirements for an organic zinc-rich moisture-cure polyurethane primer

34. SSPC-Paint 41
This specification contains performance requirements for a moisture-cured aromatic polyurethane coating with a thermoset binder and micaceous iron oxide pigment reinforcement

35. Polyureas Cured by the reaction of a polyisocyanate and an amine resin
Two distinct types of chemistry
Aromatic
Aliphatic
Pure polyurea and urethane hybrids available
Plural component equipment application
SSPC-Paint 45

36. Polyureas Advantages Abrasion resistance Chemical resistance
Very fast drying – return to service
Thick films
Disadvantages
Plural component equipment
Deep angular surface profile required
Aromatic not UV resistant

37. SSPC-Paint 45
This standard contains minimum performance requirements for two types of two-component polyurea coatings and two types of polyurea/polyurethane hybrid coatings evaluated by laboratory testing.

38. Aromatic Polyureas Better chemical resistance than aliphatic
Chalk and yellow in sunlight, but little change to other physical properties
Numerous uses
Truck bed liners, secondary containment, buried pipe coatings
Good chemical resistance to a number of industrial chemicals and hydrocarbons

39. Aliphatic Polyureas Aliphatic polyisocyanates used Stable in sunlight
Will be applied over an aromatic polyurea when UV-resistance is needed
Still require plural component equipment for application

40. Polyaspartics
Reaction between an aspartic ester resin and an aliphatic polyisocyanates
Can be applied using by standard airless equipment as well as brush and roll
Properties are similar to those of polyurethane coatings
Used as finish coat in two-coat systems or even as DTM in less corrosive environments

41. Polyaspartics Advantages Fast cure with potlife UV resistant
Thicker films up to 20 mils
Edge retention
Disadvantages
Acid resistance
Limited recoat window compared to urethanes
Humidity effects cure rate

42. Polyaspartics
Higher film builds allow the reduction in coating layers while providing the required corrosion protection
Two-coat systems with zinc rich primer
DTM in less aggressive environments

43. SSPC-Paint 39
This specification contains performance requirements for a two-component, weatherable polyurea topcoat

44. SSPC-Paint 43
This standard contains performance requirements for a two-component direct-to-metal aliphatic polyurea coating with a dry-to-handle time ranging from 30 minutes to 2 hours as determined using ASTM D 1640

45. Polysiloxanes
Any polymeric structure that contains repeating silicon-oxygen groups in the backbone, side chains, or crosslinks regardless of the substitution on the silicon atom
Include coating types based on inorganic siloxane and organic-inorganic siloxane polymer hybrids

46. Polysiloxanes C-C bond strength of 83 Kcal/mole
Si-O bond strength of 108 Kcal/mole
The stronger bond strength provides the basis for improved durability and heat resistance
Si-O is UV resistant; already oxidized; not combustible

47. Inorganic Siloxanes
Polysiloxane coatings based on pure inorganic siloxane binder are:
Can cure at ambient temperatures,
Some can be applied to hot piping
High solids
Excellent temperature resistance (>1000F)
Good chemical resistance
Can be rather brittle
UV resistance

48. Organic-Inorganic Siloxane Hybrid
Organic modification for improved flexibility
Acrylic
Epoxy
Predominant use would be as light stable finish coats
High solids ~80% solids+
Low VOC
Very good weatherability

49. Organic Modified Polysiloxanes
Advantages
Improved flexibility
Excellent UV resistance
Cleanability
No outgassing during cure
Disadvantages
Humidity required for cure, typically 50%+
Embrittlement at high film builds
Cost

50. Organic Modified Polysiloxanes
Used as an alternative to polyurethane finish coat in three coat systems
Also used as high build finish coat in two-coat system over zinc rich primer

51. Zinc Rich Coatings Two main classes of zinc rich coatings
Inorganic: ethyl silicate binders
Organic: epoxy or urethane binders
Galvanic protection of steel substrate
Exception track record of long term corrosion protection

52. Inorganic Zinc Rich Primers
Advantages
Enhanced corrosion resistance
Can be used as a stand along coating
Fast drying for productivity in shop
Disadvantages
Cure time heavily dependent on humidity
Typically hours wait prior to topcoating
Mud cracking at higher film builds

53. Organic Zinc Rich Primers
Advantages
Much faster recoat time than IOZ
Resistant to mud cracking
Lesser cleanliness required
Disadvantages
Slightly less performance than IOZ
Lower resistance to heat versus IOZ
Epoxy zinc rich can require sweat-in time

54. SSPC-Paint 20
This specification covers two types of highly pigmented zinc-rich coatings that are uniquely defined by their capabilities for protecting steel exposed at film discontinuities such as narrow scratches and holidays.
Type 1 – Inorganic binder
Type 2 – Organic binder
Level 1 — equal to or greater than 85%
Level 2 — equal to or greater than 77% and less than 85%
Level 3 — equal to or greater than 65% and less than 77%

55. SSPC-Paint 29
This specification covers highly pigmented primers that contain zinc dust as the major pigment component (minimum 65% by weight in the dry film) and are defined by their ability to protect ferrous substrates. Individual products meeting minimum performance requirements of this standard may vary in formulation, raw materials, and application characteristics.

56. General Comparison Chart – Atmospheric Exposure
Coating Type
Color and Gloss Retention
Surface Tolerant
Abrasion Resistant
Chemical Resistant
Alkyd + ++
Epoxy -
+++
Urethane (aliphatic)
MCU
Waterborne Acrylic
Polyaspartic
Polyurea (aromatic)
Organic modified polysiloxane

57. Summary
When selecting a coating for application it is important to identify the service environment, performance requirements, and type of structure and substrate in order to achieve optimum performance