ANTI-FOULING

What is marine fouling?

The growth of shell, barnacles, tubeworms, seaweed and microorganisms on sea water immersed surfaces like ship hulls.

Fouling produce roughness,reduce speed and increase turbulent flow, acoustic noise,drag and fuel consumption.

10 microns increasein hull roughness can result in 1 % increase in fuel consumption!

Trading areaMarine fouling is temperature related

Vessel activityType, severity and extent of marine fouling depend on vessel trading pattern,speed, activity and geographic location.

History

The early Phoenicians nailed copper strips to their ship’s hulls to prevent fouling.Admiral Nelson made use of copperplating on the hulls and his war ships were far more maneuverable than those used by the French (1805), a tactical advantage he used to obtain a victorious outcome.

Antifoulant biocides have included DDT, phenyl-mercury, pentachlorophenol, organolead, arsenic compounds and copper mixed into binders of gum rosin, chlorinated rubber, vinyls, acrylate.

Tributyltin TBT

High microbiological and fungicidial activity makes TBT derivates effective biocides and very toxic to a wide range of marine organisms.

Used since the early 1970’s in antifouling paints. Estimated over 70% of the world’socean going fleet were painted with TBT self- polishing based paints. Superior fouling prevention and fuel savings.

Self-polishing SPC antifouling paint

TBT biocide chemically bonded in acopolymer paint, allowing thick paintfilms with controlled, uniform releaseof the biocide to the surface. Effectiveprevention of fouling and reduction offrictional drag.

92% of TBT SPC-painted ships show low fouling with life-time of 5 years +

TBT based antifoulings perform well!

TBT acrylate after 60 months service

Test facility (Raft)

Static antifouling test panel

Marine fouling

Rotor test facility

Rotor test panel

Regulations

Research has indicated that TBT may beresponsible for the weakening of oyster and mussel shells as well as slowing the growth of various species of aquatic snails (imposex).

These concerns have led to regulatorymeasures around the world resulting ina Ban on TBT

Restrictions on the use of TBT based AF

In the US, the 1988 Organotin Antifouling Paint Control Act restricted the use of TBT-based antifoulants to ships larger than 25 mtrs. in length or those with aluminium hulls. This act also restricted the release rate of TBT. Japan unilaterally banned TBT antifouling in the early 1990’s.

In 1990, the International Maritime Organization (IMO) of the United Nations’ Marine Environment Protection Commitee (MEPC) adopted a resolution that recommended governments adopt measures to restrict the use and release rate of TBT-based antifoulants.The MEPC is made up of IMO member countries with shipping interests.

IMO proposal

““A worldwide ban on the A worldwide ban on the applicationapplication of of TBT (tri-butyl tin) antifouling systems on TBT (tri-butyl tin) antifouling systems on ships byships by 11stst January 2003” January 2003”

““A ban on the presence of TBT antifouling A ban on the presence of TBT antifouling systems on ships bysystems on ships by 11stst January 2008” January 2008” AA sealer sealer coat can be used to overcoat coat can be used to overcoat existing TBT-based antifoulingexisting TBT-based antifouling

Urges all parties involved Urges all parties involved to “refrain from to “refrain from the production, sales, marketing and the production, sales, marketing and application of antifouling systems application of antifouling systems containing organotin compounds acting containing organotin compounds acting as biocides from as biocides from 01/01/200301/01/2003””

IMO update

5-year dockings will require tin-free paint for 20035-year dockings will require tin-free paint for 2003 The treaty needs 25% of tonnage and 25 countries to The treaty needs 25% of tonnage and 25 countries to

ratify it. It becomes law 12 months after this.ratify it. It becomes law 12 months after this. EU will try to keep to the deadline of 1/1/2003 for EU EU will try to keep to the deadline of 1/1/2003 for EU

flagged tonnageflagged tonnage USA will make legislation retroactive to 2003USA will make legislation retroactive to 2003 International Chamber of Shipping in London has International Chamber of Shipping in London has

“recommended that ship operators should observe the “recommended that ship operators should observe the recommended prohibition date with effect from 1 recommended prohibition date with effect from 1 January 2003”January 2003”

So plan to use TBT-free paint from January 2003So plan to use TBT-free paint from January 2003

Main antifouling technology

1. 1. Copper based (Copper based (tin-free)tin-free),, Biocide* type Biocide* type11stst generation Self-Polishing - generation Self-Polishing - Hydration Hydration typetype22nd nd generation Self-Polishing - generation Self-Polishing - Hydrolysis Hydrolysis typetype33rdrd generation Self-Polishing - generation Self-Polishing - Hydrolysis Hydrolysis typetype

* * BiocideBiocide – a chemical which is toxic to fouling – a chemical which is toxic to foulingNote: Hydrolysis mechanism is like TBT typeNote: Hydrolysis mechanism is like TBT type

2. Copper-free, tin-free, 2. Copper-free, tin-free, Biocide* typeBiocide* type3. Biocide* Free Type3. Biocide* Free Type

Foul release, Silicone Foul release, Silicone rubber rubber typetypeOthersOthers

Biocide

Polymer

Self-PolishingSelf-Polishing

Self-PolishingSelf-Polishing

ReleaseRetentionRenewal

Controlled releaseof biocide ions

Ionized layer ofhighly concentratedbiocide

Efficient ionizationof biocide

Keeping biocideactivity

: Biocide Ion

Self-PolishingSelf-Polishing

Self-PolishingSelf-Polishing

1. 1. HYDRATION type,HYDRATION type, self-polishing self-polishing HydrationHydration – where water physically – where water physically erodes the antifoulingerodes the antifoulingAlso Also called ablative, eroding, controlled called ablative, eroding, controlled depletion and depletion and 11stst generation tin-free generation tin-free

2.2. HYDROLYSIS type,HYDROLYSIS type, self-polishing self-polishingHydrolysisHydrolysis – where water chemically – where water chemically reacts and dissolves the antifoulingreacts and dissolves the antifouling22ndnd and 3 and 3rdrd generation generation tin-free antifouling tin-free antifouling

Mechanisms for self-polishing

Mainstream copper based tin-free technologyMainstream copper based tin-free technology

TechnologTechnologyy

PolishingPolishingMechanisMechanismm

HydrolysHydrolysis actionis action

HydrolysHydrolysis actionis action

Hydration Hydration actionaction

HydratioHydrationn

actionaction

HydrolysHydrolysis actionis action

Polymer Polymer typetype

OrganoOrgano- - Silyl Silyl

Acrylate Acrylate polymerpolymer

Metallic Metallic Acrylate Acrylate polymerpolymer

Gum Gum Rosin - Rosin -

Water/Ion Water/Ion sensitive sensitive polymerpolymer

Gum Gum Rosin - Rosin -

Water/IoWater/Ion n

sensitive sensitive polymerpolymer

Organo-Organo-tin tin

AcrylateAcrylatepolymerpolymer

Chemical Chemical structurestructure

Claimed Claimed Service Service lifelife

5 years5 years Up to 5 Up to 5 yearsyears

3 years3 years 5 years?5 years? 5 years5 years

Quoted Quoted PerformanPerformance level %ce level %

9595 9090 60 to 8060 to 80 ?? 70 to 9870 to 98

Tin-FreeHydrolysis

2nd Generation

Tin-freeAblative

1st Generation

TBT Antifouling

Tin-freeAblative/

Fibrous type

Tin-FreeHydrolysis

3rd Generation

Hydrolysis gives a consistent(linear) polishing rate

-250

-200

-150

-100

-50

0

0 0.5 1 1.5 2 2.5 3

Tested period(year)

Pol

ishe

d fi

lm th

ickn

ess(

m

icro

n)

2nd generation (Green line) and 3rd generation (Blue line) demonstrate the excellent polishing performance just like TBT-AF (Red line) in below chart

The indoor rotor: 15 knots, 25°c, natural sea water

Hydrolysis gives a consistent(linear) leaching rate of biocide

Biocide Release Rate over Time

0

10

20

30

40

50

0 2 4 6

Time/ years

Co

pp

er le

ach

ing

ra

te/µ

g/d

ay/s

qcm

Hydration

Hydrolysis

Critical LeachingRate

TechnologTechnologyy

Polymer Polymer typetype

OrganoOrgano--Silyl Silyl

AcrylateAcrylate

Metallic Metallic Acrylate Acrylate polymerpolymer

Water/Ion Water/Ion sensitive sensitive polymerpolymer

Organo-Organo-tin tin

AcrylateAcrylatepolymerpolymer

Polymer Polymer coated coated panel panel immersed immersed in sea in sea water for water for 12 12 monthsmonths

% Water % Water AbsorptioAbsorptionn

1-2%1-2% 5-8%5-8% 10-20%10-20% 1-2%1-2%

PerformaPerformancence

95%95% 90%90% 85%85% 95%95%

Service Service LifeLife

5 years5 years 3-5 3-5 yearsyears

2½-3 2½-3 yrsyrs

5 years5 years

TBT Antifouling

Tin-Free Hydrolysis3rd Generation

Tin-FreeHydration1st Generation

Tin-Free Hydrolysis2nd Generation

Lower Absorbance of Water in the Resin means higher Lower Absorbance of Water in the Resin means higher performance - the reaction is controlled at the surfaceperformance - the reaction is controlled at the surface

HYDROLYSIS HYDROLYSIS AntifoulingAntifouling 33rdrd Generation Generation tin-free – Organo-Silyl Acrylate tin-free – Organo-Silyl Acrylate

22ndnd Generation Generation tin-free – Metallic Acrylate tin-free – Metallic Acrylate

HYDRATION AntifoulingHYDRATION Antifouling 11stst Generation Generation - Eroding, ablative, gum rosin, - Eroding, ablative, gum rosin, controlled depletioncontrolled depletion

95%=TBT

90%

70 - 85%

Performance

Performance of Antifouling Paints Performance of Antifouling Paints (%age of ships free from fouling)(%age of ships free from fouling)

The performance of an antifouling is deepen-The performance of an antifouling is deepen-dent on long term, consistent control of the dent on long term, consistent control of the polishing mechanism.polishing mechanism.This is best achieved with the hydrolysis This is best achieved with the hydrolysis mechanism.mechanism.33rdrd generation>2 generation>2ndnd generation>1 generation>1stst generation generationCosts per m²:Costs per m²:

44 :: 2½ 2½ :: 1 1

Summary - Antifouling PerformanceSummary - Antifouling Performance

Foul Release CoatingsFoul Release Coatings

BenefitsBenefits Environmentally Environmentally

friendlyfriendly 5-years between 5-years between

dockingsdockings Smooth surface and Smooth surface and

potential fuel savingspotential fuel savings Easily re-coatedEasily re-coated Self-cleaning or for Self-cleaning or for

slow vessels, easily slow vessels, easily cleanedcleaned

DisadvantagesDisadvantages High cost High cost Masking-off of Masking-off of

topsidestopsides Careful application is Careful application is

required for siliconesrequired for silicones Repair requires more Repair requires more

care with preparationcare with preparation