Marine coating assigment

Assignment : Marine Coatings &
Protective Coatings
Prepared by:
ABDUL JABBAR KHAN

Main function of coatings is to
protect steel structures against
corrosion and against chemicals

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Marine and Offshore
Industrial Steel Structures
Industrial Maintenance
Tanks
Transportation
– Railcars
– Large vehicles
– Sea containers [China]

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.

. 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

– 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

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.

 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

Basic Composition of Paint

Solvents (Liquids)
Pigments

Additives

Resins (Binder)

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.

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.

 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.

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.

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.

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.

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.

Coating Defects-Blistering

Coating Defects-Checking

Coating Defects-Cissing

Coating Defects-Cracking and Detachment

Coating Defects-Edge Failure

Coating Defects-Wrinkling

Coating Defects-Weld Failure

Coating Defects-Adhesion Failure

Surface preparation
 Blast cleaning

 Pickling
 Flame cleaning
 Preparation by hand

 Hydroblasting

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

Materials





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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

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

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:

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

 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

 Throughout the preparation and painting of a ship, the need
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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

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

Materials
Anti-Fouling Paints
 The ‘new’ anti-fouling technology - organometallic polymer
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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.

Underwater surface condition of a vessel to which a high quality, selfpolishing antifouling paint was applied 30 months earlier.

Self-polishing antifouling paints applied to the underwater surface of an oil
tanker.

END OF SLIDE SHOW

THANK YOU

Marine coating assigment

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