antifouling coatings types, mechanism, historical development and recent developments in antifouling paints

1. A Seminar on
DEVELOPMENT OF SOLUTION
PROCESSED ANTI- FOULING COATINGS
UNDER THE GUIDANCE OF
Dr. SAUMEN MANDAL
ASSISTANT PROFESSOR
DEPT METALLURGICAL
AND MATERIALS ENGG
Presented by
R.S.S. MANOJ KUMAR
172ML017 - M. Tech
Materials Engineering
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2. Contents
 Introduction to Biofouling and its effects
 Anti-Fouling Definition
 A/F Technologies
 Historical Development of A/Fs
 Types of Anti Fouling Coatings
 Mechanism of A/F Coatings
 Tin Free Systems and its effects
 Challenges in Tin Free Coatings
 Conclusion
 References
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3. What is Biofouling?
 Marine biofouling can be defined as the undesirable
accumulation of microorganisms, algae and animals on
submerged substrates leading to subsequent biodeterioration.
 This is a natural process which affects both living organisms
and man-made surfaces.
 Microfoulers: Tiny organisms such as Bacteria, Fungi
 Macrofoulers: Barnacles, Zebra mussels.
Reference: Image from www.heatexchanger.guide
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4. Effects of Biofouling on Unprotected Ships
 Vessel bottoms may gather 150 kg of fouling per square metre in
less than 6 months of being at sea.
 On a Large Crude Carrier with 40,000 square metre underwater
areas, this would add up to 6,000 tonnes of fouling.
 Just a small amount of fouling can lead to an increase of fuel
consumption of up to 40-50%, resistance to movement is
increased due to high frictional drag.
Reference: Courtesy of Hempel’s Marine Paints A/S
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5. How do anti-fouling systems save a
shipowner money?
 Direct fuel savings by keeping the hull free of fouling
organisms.
 Extended dry-docking interval, when the anti-fouling
system provides several years of use.
 Increased vessel availability - since it does not have to
spend so much time in dry dock.
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6. Anti-fouling Technologies
Antifouling technologies refer to the means of
combating biofouling:
1. Hull Cleaning with harsh chemicals
2. Mechanical Removal and
3. Application of anti-fouling coatings to submerged surfaces.
Hull Cleaning Mechanical Removal
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7. Historical Development of Anti-Fouling
Coatings
Timeline for Antifouling Coatings
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8. Types of Anti Fouling Coatings
Soluble Matrix
Insoluble Matrix
(Contact leaching)
SPC
(Self- polishing)
 Based on Biocide Release Mechanisms
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9. What makes a biocide good in an antifouling
system?
 Broad spectrum activity
 Low water solubility
 No bioaccumulation in the food chain
 Not persistent in the environment
 Compatible with paint raw materials
 Favourable price/performance
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10. Mechanism of Anti-fouling systems
Schematic illustration of the behaviour of a biocide-
based antifouling system exposed to sea water.
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11. Self-Polishing Copolymer System (SPC)
In which the organotin compounds are chemically bonded to the
polymer base.
The leaching rate of these paints is controlled because the biocide is
released when seawater reacts with the surface layer of the paint and
the reaction to release the biocide begins again with the next layer.
In this way, the leaching rate is the same throughout the life of the
paint and possible for ships to go up to 60 months without
repainting.
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12. Harmful Effects of TBT on Environment
 Water and Sediments
 Shell Malformations
 Imposex
 Marine Mammals
 Reduced Resistance to infection
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13. Tin Free Systems
Biocides
Booster Biocides
Natural Biocides
Non-Toxic
Tecnology
Non Stick
Fouling
Other Systems
IMC & Nippon
Paint
Kansai Paint
Hempel’s Marine
Paint
Sigma Coatings Pigments
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Various Tin Free Systems Emerging in the Market

14. Working of TBT Free Systems
Composed of seawater soluble
matrices containing tin-free
biologically active ingredients.
The biocides are dispersed and
contained throughout the matrix.
At the seawater/paint interface, the
biocide leaches at a controlled rate.
The matrix dissolves, revealing
freshly available biocide, enabling a
performance to be achieved.
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15. Challenges in Tin Free Coatings
(1) Poor self-smoothing.
(2) Increasing leached layers with immersion time.
(3) Biocide release not constant.
(4) Little activity during idle periods.
(5) Short lifetimes (up to 3 years).
(6) Higher costs before applying new coats (sealer coating needed).
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16. Conclusion
 Marine biofouling is a complex biological phenomenon
― Displacing an organism from its niche habitat may allow
another organism to take it over.
 Combatting marine fouling is an on-going quest
— Improvements are driven by legislative and operational
factors.
 Different surfaces will require different approaches
—Ships and e.g. offshore rigs may require different systems.
 Previous effective toxic systems will not be available
—The recent banning of TBT has renewed the search for
environment-friendly biocides.
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17. References
 Antifouling technology—past, present and future steps towards efficient and
environmentally friendly antifouling coatings by Diego Meseguer Yebra, Søren
Kiil, Kim Dam-Johansen., Progress in Organic Coatings 50 (2004), Elsevier.
 Antifouling Coatings: Recent Developments in the Design of Surfaces That Prevent
Fouling by Proteins, Bacteria and Marine Organisms by Indrani Banerjee, Ravindra
C. Pangule, and Ravi S. Kane., Advance Materials 2011, 23, 690–718.
 Anti-fouling systems, International Maritime Organization, IMO 2002.
 Marine paints: The particular case of antifouling paints by Elisabete Almeida,
Teresa C. Diamantino, Orlando de Sousa., Progress in Organic Coatings 59 (2007)
2–20, Elsevier.
 Modern approaches to marine antifouling coatings by L.D. Chambers, K.R. Stokes,
F.C. Walsh, R.J.K. Wood., Surface & Coatings Technology 201 (2006) 3642–3652,
Elsevier.
 Understanding Marine Fouling by Simon Dennington., University of Southampton,
UK, 2009.
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18. Thankyou for
your kind
attention
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