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Marine and Protective Coatings

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Limitations with aliphatic alcohol's which must be used in combination with better solvents. ... Aliphatic solvents are unsuitable with standard epoxy resins ... – PowerPoint PPT presentation

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Title: Marine and Protective Coatings


1
Marine Coatings Protective Coatings.
2
Marine Protective Coatings
  • Main function of epoxy coatings is to
  • protect steel structures against
  • corrosion and against chemicals
  • Marine and Offshore
  • Industrial Steel Structures
  • Industrial Maintenance
  • Tanks
  • Transportation
  • Railcars
  • Large vehicles
  • Sea containers China

3
Key Market Segments in Europe
Source SRI Consulting
Worldwide consumption of anticorrosion coatings
estimated at ca. 1.1 Millions MT, with a value of
ca. 5 Billions in 2001. MPC coatings represent
4 of the global coatings volume, but 8-9 of
the total value.
4
Marine Coatings
Ballast tanks
  • The role of epoxy coatings is to protect against
    corrosion each part of ships, which are
    continuously exposed to severe conditions, i.e.
    sea water immersion, splashes of sea water, UV
    rays
  • maintain the value of the assets
  • ensure vessel safety
  • protect cargoes, e.g. grain or liquids

5
Marine sub-segments
  • Key Performances requirements
  • Resistance to corrosion
  • Chemical resistance
  • Mechanical resistance, e.g. abrasion
  • Weatherability
  • Water ballast tanks
  • Under water hulls and sides
  • Cargo tank linings
  • Cargo holds
  • Boot-topping and splash zones
  • Topsides and external superstructures
  • Offshore oil drilling platforms

6
Typical Protective Coatings Markets
Pictures downloaded from Akzo Nobel Coatings
web-site
7
Non-generic Competition

  • Source SRI report 2001
  • Epoxy Resins are essential raw materials for
    Marine Protective Coatings.
  • Epoxy systems offer an outstanding balance
    between performances durable corrosion
    protection and costs.

8
Desired Properties of MPC Coatings
  • Each end-use requires an optimum balance between
  • Ambient application window
  • Ease of applying spray, brush, roll
  • Solids content, VOC content
  • Film thickness
  • Drying time
  • Sufficient hardness / flexibility
  • Edge covering
  • Impact resistance
  • Overcoating time window,
  • Long term corrosion protection
  • Long term adhesion, adhesion in wet
    environment e.g. in water immersion conditions
  • Resistance against chemicals acids, solvents,
    caustic,

9
Properties of ambient cured epoxy coatings
  • Chemical cure 2 pack systems
    Limited pot life
  • Excellent adhesion on many substrates
  • Excellent corrosion protection
  • Superior resistance to water, chemicals, solvents
    oil
  • Extremely resistant to mechanical stress
  • Good surface preparation required
  • Curing rate depends upon temperature.
  • Chalking when exposed to sun light
  • Over coat-ability limitations Minimum maximum
    intervals between layers to be respected
  • Cathodic disbondment resistance required in some
    applications

10
Main Dow resins employed in MPC
  • Bisphenol A epoxy resins solutions
  • D.E.R. 331
  • D.E.R. 337X80
  • D.E.R. 660X80
  • D.E.R. 671
  • D.E.R. 671X75
  • D.E.R. 671XB70
  • Bisphenol F epoxy resin
  • D.E.R. 354
  • Epoxy novolac resins
  • D.E.N. 425
  • D.E.N. 431
  • D.E.N. 438X80


Trend towards Liquid Epoxy Resins and Semi-Solid
Epoxy Resins expected in Europe due to more
stringent VOC regulations
Best chemical resistance
Trademark of the Dow Chemical Company
11
Schematic epoxy coatings formulation
  • 2- Pack Solvent Borne Systems
  • Component A Component B
  • Epoxy Resin(s) Curing Agent(s)
  • Pigments Extenders Pigments Extenders
  • Solvents Solvents
  • Additives Additives Accurate Mix ratio.
  • Thorough mix prior to use. Pot-life of 1 - 8
    hours. (Pot life depends on temperature,
    quantity, type of resin and hardener)
  • Modifiers e.g. hydrocarbon resins or reactive
    diluents can be used

12
Typical curing agents used in MPC
  • Curing agents mostly based on amine
    chemistry.
  • Polyamidoamines VersamideTM type
  • Amidoamines
  • Epoxy - Amine adducts
  • Mannich bases Faster cure
  • Phenalkamines Low temperature cure
  • Typical accelerators
  • Tertiary amines e.g. AncamineTM K54 type
  • Alkyl phenols
  • Remarks
  • Induction time needed with some curing agents to
    overcome the limited compatibility with epoxies
    and to minimize the blushing effect.
  • Curing agents frequently used at
    under-stoichiometric levels to minimize blushing
    typical NH / epoxy stoichiometry 80

13
Example of Anticorrosion Coating System
  • Top Coat Appearance Protection against
    UV-light
  • Mid Coat Barrier Protection effect. Intercoat
    adhesion
  • Primer Corrosion protection Adhesion

ca 400 µm
Epoxy, PU, Alkyd, Acrylate
Topcoat 150 µm
Epoxy
Mid coat 150 µm
Epoxy
Primer 70 µm
Metal Substrate
14
Examples of commercial coatings systems (1)
  • Epoxy zinc primer 30 µ
  • Epoxy primer 50 µ
  • Epoxy tie coat 100 µ
  • Epoxy top coat 50 µ or weatherable PUR
  • Epoxy zinc primer 30 µ
  • Epoxy aluminium primer 300 µ
  • Epoxy top coat 300 µ

Steel protection

Superior steel protection, e.g. off shore
15
Typical Epoxy Polyamide Primer Formulation.
(Red oxide Zinc Phosphate)
  • Epoxy resin component Parts by weight
  • D.E.R. 671X75 Epoxy Resin Solution 18.7
  • Pigment grinding additive 0.5
  • Zinc Phosphate 10
  • Silica Powder 5
  • Iron Oxide Red 20
  • China Clay 5
  • Fumed silica thickener 1
  • Xylene 17
  • n-Butanol 7
  • Curing agent component
  • Versamide 115/70X 10.6 Or similar
    polyamido-polyamine hardener

16
Typical Properties of type 1 epoxy resin /
polyamide formulation.
  • Pot-life min 8 hours
  • Coverage 6 - 7 m2 per liter _at_ 100
    µm thickness
  • Surface hardness 300 s Persoz Pendulum
  • Erichsen Flexibility min 7 mm
  • Salt Spray Test min 1000 hours
  • Low Temperature Cure 10 C
  • Adhesion to all kinds of substrates
  • Note Properties strongly depend on the surface
    preparation

17
Interdependency between Pot life, Drying Times
and VOC
Pot life _at_ 20C, hours
8 Hrs
High VOC D.E.R. 671
Low VOC, lt250 g / litre
1 Hr
Solvent free
Drying times (full dry) hours at low temperature
8 Hrs
48 Hrs
24 Hrs
16 Hrs
Low VOC or VOC free epoxy systems exhibit a
poorer balance between drying time and pot life
than high VOC systems.
18
Drying times and pot life - Additional comments
  • The coatings are often stored in a heated
    warehouse to prevent addition of solvent to
    adjust the viscosity to spray viscosity.
  • The epoxy amine reaction is exothermic
    Increase of the pot temperature after mixing of
    the 2 components
  • Coatings drying time dominated by the temperature
    of the substrate and by the degree of
    ventilation.
  • Faster reaction kinetics in the pot than in
    applied paint film, especially in winter time.
  • Generally lower viscosity epoxies have a lower
    EEW (a higher oxirane content)
  • Higher levels of hardener needed or hardeners
    with higher NH content needed.
  • High solids / solvent free coatings have a higher
    concentration of reactive groups in the mixed
    paint, which goes against pot-life.

19
Surface preparation
  • The removal of
  • rust salt mill scale weld spatter grease
    oil dirt old paint depending upon quality
  • and rounding of sharp edges
  • are critical to achieve optimum performances of
    epoxy coatings
  • Surface preparation is labour intensive and
    represents a significant part of total costs of
    the coating process.

20
Surface preparation techniques
  • Blast cleaning Ideal
  • Hydro jetting
  • Mechanical wire brushing
  • Manual brushing Poor
  • Note Hydro jetting is increasingly popular.
    But it poses some specific problems

21
Surface preparation rating
  • SA 1 Light blast cleaning
  • SA 2 Thorough blast cleaning
  • SA 2 1/2 Very thorough blast cleaning
  • SA 3 Blast cleaning to visually clean
  • St 2 Thorough manual cleaning
  • St 3 Very thorough manual cleaning
  • Optimum coatings performances achieved with SA
    2 1/2 cleaning.

22
Typical cost structure of a Paint Job Euros /
m2 / 150 µm ( Brevoort Consultancy )
  • Surface Cleaning
  • Hand cleaning 4.6
  • SA 2.5 blasting 8.0
  • SA 3 Near White blasting 9.2
  • Application
  • Brush / Roller 2.1
  • Spray 2.6
  • Coating
  • Alkyd 1.6
  • Epoxy 1.9

Cost of coating is less than 20 of total cost
of painting job
23
Estimated Service Lives of High-Performance
Anticorrosion Coatings (years)
Source GH Brevoort et al
Epoxy based anticorrosive coatings provide long
lasting service life and corrosion protection
24
Single feed Airless pump spray gun
Typical pressure ca 250 Bars. No pressurized
airflow. High fluid pressures force the coating
through a small orifice ? Atomization Minimum
pot-life 45 min (time to spray 25 liters of
mixed paint) Otherwise risk of gelation in the
pumps, hoses and spray guns
Twin feed airless technology exists but is not
widely accepted, because of cost, less
user-friendliness and lower robustness
25
Technology Trends Some unmet needs
  • Higher solids coatings
  • Solvent-free coatings
  • Water borne coatings
  • Faster cure
  • Low temperature cure to extend application window
  • Surface tolerant coatings to reduce surface
    preparation costs
  • Improved overcoatability window
  • Flexible Epoxy Resins
  • Improved balance between drying time and pot-life

VOC reduction

Productivity gains
26
Epoxy Resins in Marine Protective Coatings
  • Epoxy Resins are essential raw materials for
    these high demanding coatings segments, thanks to
    the outstanding benefits they provide
  • Corrosion protection
  • Chemical resistance
  • Mechanical properties, e.g. adhesion
  • Low VOC levels achievable
  • Marine Protective Coatings, a large and growing
    market for epoxy resins

27
End of the Marine Protective Coatings Part
Any questions I could possibly answer on MPC
applications ?
Further Technical as well as Product Stewardship
related information can be found on
www.Dowepoxy.com. e.g. Dow Epoxy Products
Portfolio incl. Corresponding technical
datasheets, Dow Liquid Epoxy Resin Brochure Dow
Epoxy Novolac Brochure Dow Epoxy Resin Product
Stewardship Manual Dow Epoxy Curing Agents
Product Stewardship Manual
28
(No Transcript)
29
Solvents
  • Role of solvents Reduce the viscosity and aid
    the film formation
  • Types of solvents
  • Aromatics, ketones, glycol-ethers, acetates are
    suitable.
  • Limitations with aliphatic alcohol's which must
    be used in combination with better solvents.
  • Aliphatic solvents are unsuitable with standard
    epoxy resins
  • Key parameters
  • Solvency Power
  • Hansen Solubility Parameters / Compatibility
  • Evaporation profile
  • Flash-point
  • Solvent retention effect
  • Influence on reactivity and pot-life
  • Smell
  • EHS properties

30
Pigments Fillers
  • Opacity and colour
  • Titanium dioxide
  • Iron oxides
  • Organic pigments
  • Anticorrosion
  • Zinc dust
  • Zinc phosphates
  • Borates
  • Whole range of new environment friendly
    anticorrosive pigments
  • Extenders
  • Barium sulphates
  • Talc
  • Silica
  • Calcium carbonates
  • Barrier
  • Aluminium flakes
  • Miox
  • Mica
  • Micaceous iron oxide
  • Abrasion resistance
  • Glass flakes

31
Additives
  • Accelerators
  • Sagging control / Rheology modifiers
  • Wetting agents
  • Pigment and extender anti-settling additives
  • Film Flow additives
  • Craters, Orange Peel, Benard Cells
  • Foaming / Air release
  • Surface Tension 0.1 of additive can
    significantly change the performances

32
Typical Wt Composition of D.E.R. 671X75 based
coatings
Typical VOC content 300 350 g / liter
33
Typical Wt Composition of low VOC epoxy coatings
Typical VOC content 200 250g / liter Low VOC
coatings are based on liquid epoxy resins or on
low viscous semi-solid epoxy resins
34
Types of epoxy coatings
  • Solvent borne
  • High solids
  • Solvent free
  • Water Borne
  • Shop primers
  • Zinc rich primers
  • Epoxy primers
  • Zinc phosphate primer
  • Glass flakes reinforced coatings.
  • Tie coats
  • Putty / Caulking
  • Transparent varnishes
  • Winter grades
  • Etc..

35
Examples of commercial coatings systems (2)
  • Zinc silicate 70 µ
  • Epoxy tie coat 50 µ
  • High built epoxy coat 200 µ
  • Weatherable PUR 50 µ
  • Epoxy primer 30 µ
  • Epoxy mineral flakes coat 300 µ

Steel protection, e.g. off shore, above splash
zone

Interior tank lining
36
Typical Composition of High Solids Epoxy Primer
  • Epoxy Resin Component Parts by weight
  • D.E.R.331 Epoxy Resin 21
  • Pigment grinding additive 0.5
  • Iron Oxide Red 10
  • Barium sulphate filler 20
  • Mica filler 20
  • Fumed silica thickener 2
  • Xylene 10
  • Butanol 5
  • Curing Agent Component
  • Ancamine 2253 Polyamide type 12
  • Note Hydrocarbon resins e.g. Necires grades
    often employed as co-binders to reduce the
    brittleness of pure high solids epoxy
    coatings.

37
Drying time versus temperature of commercial
coatings
Drying time of epoxy coatings severely affected
by temperature Drying time strongly influenced by
solids content Note More reactive curing agents
generally employed in winter systems
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