Marine coating assigment

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Marine coating assigment

  1. 1. Assignment : Marine Coatings & Protective Coatings Prepared by: ABDUL JABBAR KHAN
  2. 2. Main function of 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. 3. Pulp and paper 3% Food & beverage plants 8% Others 7% Marine 30% Water and sew age 7% Bridges & infrastructure 13% Oil & gas production & transmission 11% Public Utilities 11% Petrochemical plants 10% Worldwide consumption of anticorrosion coatings estimated at ca. 1.1 Millions MT, with a value of ca. $ 5 Billions in 2001. M&PC coatings represent 4% of the global coatings volume, but 8-9% of the total value.
  4. 4. . The role of 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 – – Ballast tanks – Ballast tanks
  5. 5. – Water ballast tanks – Under water hulls and sides Key Performances requirements – Cargo tank linings Resistance to corrosion – Cargo holds – Boot-topping and splash zones – Topsides and external superstructures – Offshore oil drilling platforms Chemical resistance Mechanical resistance, e.g. abrasion Weatherability
  6. 6. Consumption of High-Performance Anticorrosion Coatings by Resin Type in Europe 2% 3% 10% 5% 2% 45% Epoxy Urethane (aliphatic) Urethane (aromatic) Inorganic Zinc Vinyl Acrylic 6% 7% Chlorinated Rubber Alkyd 20% Other 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.
  7. 7.  Top Coat:  Mid Coat:  Primer: Appearance & Protection against UV-light Barrier Protection effect. Intercoat adhesion Corrosion protection & Adhesion Epoxy, PU, Alkyd, Acrylate Epoxycoating Epoxy coating Metal Substrate
  8. 8. Basic Composition of Paint Solvents (Liquids) Pigments Additives Resins (Binder)
  9. 9. Paint  Pigments: These are powders which impart colour and hiding power to paints  Some pigments have mainly decorative function while others have protective function  Few pigments have very special function, e.g cuprous oxide, for anti-fouling paint ; leafing (flake) aluminium reflects sunshine and reduce heating.
  10. 10. Paints: Paints are used to protect metals, timber or plastered surfaces, brick work and concrete work from the corrosive effects of weather, heat, moisture or gases etc and to improve their appearance. Composition of the paints can be easily adjusted in the process of their manufacture, depending upon the purpose for which they are required and quality of the work required.
  11. 11.  CONSTITUENTS/ COMPOSITION OF PAINTS: Paints essentially contain a base which provides body, there is a carrier, also known as vehicle in which the base is dissolved, and it is the carrier which helps the base to spread all over when applied. The pigments are also added to give the desired colours. Some common examples of substances used as base in paint are zinc white, white lead, red lead. Common substances used as carrier in the paints is such as, water (in water paints), linseed oil and poppy oil etc.
  12. 12. Besides these essential ingredients, several other substances are added, such as fillers to give bulk to the paint without affecting its properties and to make it economical, solvents or thinners which dissolve other constituents and make the paint thin and driers which help in rapid drying, setting and hardening of the painted surface. Some commonly used fillers for paints are chalk, silica and charcoal, commonly used solvents are turpentine oils, petroleum sprit, commonly used driers are red lead, litharge and manganese sulphates etc.
  13. 13. USES OF PAINTS: The main functions performed by paints are:  It is used to give a high-class finish,  It is used to give attractive colours,  It is used to give pleasing surfaces design and appearance,  It is also used to protect the material from atmospheric effects,  To protect various substances from corrosion,  To protect wooden articles from wet-rot and many other types of defects,  To make the materials long lasting.
  14. 14. PROPERTIES OF GOOD PAINTS : The main properties of a good paint are as follows:  It should give a thin and uniform coating.  It should be hard and durable on drying.  The painted surface should not crack on drying.  It should be resistant to weathering and corrosive action.  It should be water-repellent (except water paints).  It should have good spread.  It should have good adhesive power. It should give a good finish with attractive colour, design and appearance.  The colours should be fast and permanent.  It should be cheap and economical.
  15. 15. Categorization of coating deficiencies: While coating failures may occur for number of reasons, they can generally be categorized into four main groupings: 1. Coating manufacturer related or caused 2. Owner/specifier related or caused 3. Coating applicator related or caused 4. Environmental service related or caused.
  16. 16. Coating Defects-Blistering Coating Defects-Checking Coating Defects-Cissing Coating Defects-Cracking and Detachment
  17. 17. Coating Defects-Edge Failure Coating Defects-Wrinkling Coating Defects-Weld Failure Coating Defects-Adhesion Failure
  18. 18. Surface preparation  Blast cleaning  Pickling  Flame cleaning  Preparation by hand  Hydroblasting
  19. 19. Blast Cleaning  Most efficient method of surface preparation  Two types of Blast equipment: a. an impeller wheel plant where abrasives are thrown at high velocity against the metal surface. Self contained and - collect dust and re-circulate clean abrasive – plant use b. a nozzle type where a jet of abrasive impinges on the metal surface – fitted with vacuum dust recovery equipment  Cast iron and steel grits or steel shots is preferred for metallic abrasive but non-metallic abrasives are also use.  After blasting, brush clean surface and apply a priming coat
  20. 20. Sa 3 Sa 2.5 Sa 2 Sa 1
  21. 21. Materials     Pickling Immersion of metals in an acid solution To remove mill scale and rust from surface After immersion in acid , metal requires thorough hot water rinse Treatment followed by application of a priming coat
  22. 22. Materials Flame Cleaning  To remove mill scale and rust from surface  Does not entirely remove the mill scale and rust  Useful for cleaning plates under inclement weather condition, the flame drying out the plate
  23. 23. Hydroblasting / Water Jetting The terms water washing (usually used to remove salts, slimes and light fouling from vessels in dry dock) and hydroblasting (used to remove rust and paint) can easily become confused. To clarify the situation, the following pressure guidelines are given:
  24. 24. Painting Procedures and Precautions  Successful application of paint requires correct technique during painting and suitable conditions during which the application takes place  Painting should take place in warm dry weather but not in direct sunlight  Presence of moisture in air or on metal surface may damage paintwork or slow down the curing process
  25. 25. Painting Procedures and Precautions  Principal methods of paint application are the airless spray, the air assisted spray, the roller and the brush  Brush and roller is employed when the surface is rough and small inaccessible places are to cover  The methods is slow, labour intensive and difficult with certain type of paints  Air-assisted spray has been replaced by the airless spray technique  Airless spray is the fastest and clean method.  Dry film thickness of up to 300 microns possible
  26. 26. Painting Procedures and Precautions  Throughout the preparation and painting of a ship, the need     for good, safe, suitable means of access is paramount Freedom of movement to maintain appropriate distance for paint spraying is essential Safety is required with paints.. toxic/poisonous, flammable and irritant to skin. Adequate ventilation and protection necessary Avoid possibility of fire and explosion
  27. 27. Drying time versus temperature of commercial coatings 40 Drying time Hours 35 100% solids 30 68 % Solids 25 82% Solids 20 15 10 60 % Solids 5 0 -10 -5 0 5 10 15 20 25 30 35 40 Temperature, °C 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
  28. 28. Materials Anti-Fouling Paints  The ‘new’ anti-fouling technology - organometallic polymer     system (Self-polishing co-polymer) It incorporates an organotin toxicant. A large number of organotin polymers have been synthesized. The coating becomes smoother with passage of time since turbulent flow of sea water selectively removes the ‘peak’ of the anti-fouling coating where it covers roughness in the underlying hull surface. As the toxicant is an integral part of resin matrix, the length of time during which it is active depends on the thickness of the layer applied.
  29. 29. Underwater surface condition of a vessel to which a high quality, selfpolishing antifouling paint was applied 30 months earlier.
  30. 30. Self-polishing antifouling paints applied to the underwater surface of an oil tanker.
  31. 31. END OF SLIDE SHOW THANK YOU

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