1.1 Introduction to Paint Technology

Marine CoatingsAll products supplied and technical advice or recommendations given are subject to our standard Conditions of Sale.

Agenda.

1. 10.00. – 11.00. Introduction to paint technology.

2. 11.00. – 12.00. Surface Preparation and Paint Application

3. 12.00. – 13.00. On Board Maintenance.


Introduction. Course Presenter.

Doug Gilbert.• I am International Paint’s Regional Marine Technical

Manager, for UK, Germany and Benelux.• I have worked in corrosion control industries since 1976. • I have been with International Paint Marine for 23 years,

and held various technical positions, all of them involved with ship painting, both at new build, M&R and during OBM.

• I spent 6 years seconded to BP working as a coating superintendent.


Introduction to Paint

•Full-size image


Why are ships painted?

Corrosion Protection.• Paint is the primary means of protecting the steel from corrosion. It does this by acting as a barrier between the steel and the environment.

(Atmosphere or seawater or cargo.) • It excludes both oxygen and water, and has a high electrical impedance. • However all paints are porous and break down over time. To make anticorrosive paints last, they must have barrier properties and they must be applied at the specified thickness.


Why are ships painted? Corrosion Protection.

.


Why are ships painted? Cosmetic Appearance.

Cosmetic Appearance.• This is important to vetting inspectors and corporate

image.

• It is not a trivial issue. • However all cosmetic finishes fade with time, and must be

over-coated to maintain standards.

• This can be done either at dry-dockings or during scheduled on board maintenance.

• Cosmetic paints must have good colourfast pigments.


Why are ships painted? Cosmetic Appearance



Antifouling.• Ships have to maintain a clean hull to reduce drag when sailing. • Drag causes loss of speed and increases fuel costs and CO2 emissions.

• Antifoulings work by leaching biocide into the water, or by achieving a non-stick surface.

• To do this they require special binders and pigments.


Why are ships painted? Antifouling.



Cargo Protection.• Product and chemical tankers must have tank linings to protect the steel from the cargo.

• They also protect the cargo from cross contamination with other cargoes.

• Coatings must be easy to clean.

• To do this the binders and pigments have to be resistant to a wide range of chemicals.


Why are ships painted? Cargo Protection.


Abrasion resistance.



• Abrasion resistance to ice damage.



Specialist reasons.

• Cargo abrasion resistance.



Specialist Reasons.

• Low solar absorption.

• Radar attenuation.

• Fire retarding & protection.

• Safety. Non-slip decks.



• Non-skid coatings.

• Many deep sea ships have heli decks or heli winch pad areas.


Why are ships painted

• All paints are especially formulated by the chemists for a specific job.

• They do this by using different types of binders, pigments and solvents.

• Different types of paint are not interchangeable.

• It is therefore vital that you use the correct product for the job. It must also be applied at the correct thickness.


What is Paint?

ISO4618-1

A pigmented COATING MATERIAL in liquid, paste or powder form which when applied to a SUBSTRATE forms an opaque FILM having protective, decorative or specific technical properties


History of Paint

•40,000 BC Blood, Egg, Animal Fat

•3000 BC Urushiol based lacquer (China)

•0-500 AD Linseed Oil Based products

•1920s Alkyds

•1920s Ureaformaldehyde Chemistry

•1950s Isocyanate Chemistry

•1950s Epoxy Chemistry

•1960s Silicates

•1970s SPC TBT technology

•1980s Isocyanate replacements

•1990s Tin free antifoulings


Paint Composition

BINDER (RESIN)

PIGMENTS

SOLVENT


Binders

Paints are generally named by their binder component • Acrylic• Alkyd• Chlorinated Rubber• Epoxy• Epoxy Phenolic• Polysiloxane• Polyurethane• Vinyl• Zinc Silicate• + more!


Binder Function

Binder used determines physical and chemical properties of the coating

Binder forms a continuous adherent film

It can be modified using plasticisers to provide additional physical or chemical properties, e.g. flexibility

Must be present in paint formulation, no binder = no paint

LIQUID RESINS SOLID POLYESTER

COAL TAR

SOLID EPOXY RESINS


Binder Classification

Binders can be classified into the following 2 groups:

1. Non-Convertible Resin Systems

2. Convertible Resin Systems


Non-Convertible Binders

High molecular weight molecules. Must be dissolved in solvent

Drying mechanism is solvent evaporation only

Once dried, it is possible to redissolve the film using the appropriate solvent

Undergo no chemical reaction during ‘drying’


Non-convertible coatings

Non convertible coating types are:

1. Chlorinated Rubbers• Interchlor

2. Vinyls• Interprime 65• Intertuf 203.

3. Bituminous• Intertuf 16

4. Acrylics• Intersheen 579• Acrylate antifouling binders


Pros and Cons of non-convertible coatings

PROS

• Dry at a wide range of temperatures

• Single pack Products

• Simple to Use

• Long overcoating intervals

CONS

• Low Solids• High VOCs• Multiple coats

required to achieve film build

• Thermoplastic

• Poor Solvent Resistance


Properties of Non-Convertible Coatings

Paint Type Mechanical Properties

Cosmetic Properties

Overcoatability

Acrylic Moderate Very Good Good

Chlorinated Rubber

Moderate Moderate Very Good

Bituminous Poor N/A Very Good

Vinyl Good Good Very Good

Paint Type Resistance to

Water Acid Alkali Solvent

Acrylic Moderate Good Good Poor

Chlorinated Rubber

Good Good Good Poor

Bituminous Very Good Good Good Very Poor

Vinyl Good Good Good Moderate


Convertible Binders

• “Dry” by a chemical reaction• Oxidative Drying• Moisture Curing• Multi-pack Systems

• Can not be redissolved in solvent once dried

• Binders are low molecular weight molecules


Convertible Coating Types

Multi Pack Systems

• Epoxy• Intergard

343• Intershield

300• Intergard

263

• Polyester

• Polyurethane• Interthane

990

• Silicone Hybrid• Interfine 979

Moisture Curing

• Zinc Silicates

• Interplate 937

• Interplate 855

• Interplate Zero

• Urethanes

Oxidative Drying

• Alkyd

• Interlac 665

• Interprime 198

• Epoxy Ester


Binder Cure Mechanisms (Oxidative Drying)

Oil chains contain double bonds• Drying mechanism is by radical addition of oxygen

across these double bonds

Binders can be modified to improve properties

Oil length determines drying time and mechanical properties

• Short oil = Fast Drying• Long oil = Slow drying

Drier additives can be added to accelerate drying


Binder Cure Mechanisms (Moisture Cure)

Drying mechanism is by reaction of water in the atmosphere with a functional group on the binder chain

Relies on having sufficient humidity in the atmosphere (usually >50%RH)

Functional Group can be:• Silyl functional group (Silicones/Silicates)

• Zinc silicates, heat resistant silicones, shop primers

• Urethane functional groups (Urethanes)• Moisture cure urethanes, polyurethanes etc.


Binder cure mechanisms (Multipack systems)

Drying mechanism is a chemical reaction between functional groups to form a large polymer network

Some mechanisms are:• Epoxy

• Reaction with Amine, Isocyanate, Acrylic or Homopolymerisation

• Polyurethane• Reaction of Polyester or Acrylic with Isocyanate

• Silicone/Organic Hybrids• ***Proprietary Information***


Pros and Cons of Convertible Coatings

Not simple to list

Technologies should be selected for end-use

Very easy to get wrong!!!


Properties of Convertible Coatings

Paint Type Mechanical Properties

Cosmetic Properties

Overcoatability

Alkyd Moderate Good Good

Epoxy Very Good Poor Poor

Epoxy Phenolic Very Good N/A Poor

Polyurethane Very Good Very Good Moderate

Zinc Silicate Very Good N/A Variable

Paint Type Resistance to

Water Acid Alkali Solvent

Alkyd Moderate Poor Poor Moderate

Epoxy Good Very Good Very Good Very Good

Epoxy Phenolic Good Excellent Excellent Excellent

Polyurethane Good Very Good Very Good Very Good

Zinc Silicate Very Good Very Poor Very Poor Excellent


Pigments

• Pigments are finely ground solids• They are held within the binder network• They impart a specific property to the paint


Pigments

When added to the binder:• Give Colour to the film• Provide Opacity • Protect the binder against UV• Provide film strength• Modify Rheology of the paint• Release effects – Anti-corrosion/Antifoulings• Provide conductivity• Provide barrier properties

ISO4618-1A pigmented COATING MATERIAL in liquid, paste or

powder from which when applied to a SUBSTRATE forms an opaque FILM having protective, decorative or specific technical properties

***A PAINT WITHOUT PIGMENTS IS A VARNISH***


Pigment Types

Prime Pigments• Provide Colour• Provide Opacity• Protect binder from UV• Categorised as Organic

or Inorganic

Extender Pigments• Provide film strength• Improve application

properties• Improve physical

properties• Reduce gloss• Improve rheology• Maintain PVC of the

coating

Functional Pigments• Provide Corrosion

Resistance• Provide Impermeability• Aid Fire Retardancy• Provide Antifouling

performance• Provide Conductivity

Pigmentary Additives• Control rheology• Reduce Gloss• Stabilise binders• Moisture scavengers


PRIME PIGMENTS

TITANIUM DIOXIDE

PHTHALOCYANINE BLUE


Prime pigments in Binder

Steel

x1000

RED PIGMENT

BINDER

View of the coloring pigmentparticles held in the paint film


Prime Pigments and protection

Steel

Water WaterOxygen Oxygen

Simplified view of the pigmentparticles held in the paint film

Unrestricted access to the steelPrime pigments do not provide anticorrosion

protection


Extender Pigments

CHALK

TALC

MICA

BARYTES


Extender Pigments in a coating film

Steel

View of the extending pigmentparticles held in the paint film

x1000

Note: These chemically inert materials do not prevent access of water and oxygen to the substrate


Functional Pigments (Anti-Corrosive)

Anti-Corrosive Pigments

• Protect metal substrates by either chemical or electrochemical means

ZINC DUST ZINC PHOSPHATE


Functional Pigments (Barrier)

• Pigments have a large surface area, with small thickness (like a piece of paper)

• Increases the impermeability of the coating to water, oxygen and ions

Micaceous Iron Oxide

Aluminium Glass Flake


Barrier Pigments – Protective mechanism

Simplified view of the barrier pigmentparticles held in the paint film

Restricted access to the steel – increased critical path length

Pigment adding to the anticorrosive protection

Steel

WATER WATERIONS

OXYGEN


Solvents

Volatile Liquids used to dissolve solid resins and aid achieving an acceptable application consistency.


Role of Solvents

Solvents completely dissolve or disperse the binder

They are not interchangeable. Thinning or cleaning solvent for one binder will not necessarily work on another binder

Solvents reduce the viscosity of the paint for application

On drying, the solvent evaporates from the film: it plays no part in the dry film

Can use solvents to impart specific properties on the paint:

• Pot life extension• Surface Flow and gloss• Tack time


Factors affecting drying of paint

Temperature

Air Replacement

Film Thickness

Paint Mixing

Humidity


Factors affecting Drying – Temperature

• The rate of evaporation of solvents increases with temperature

• As a general rule, drying times halve with every 10°C rise in temperature

• At very low temperatures, some coating types have a drying rate which is too slow to be practicable

• The longer a coating remains wet or un-cured, the greater it is at risk from the elements

• At low temperature, pot life of two pack water based products is reduced


Factors affecting Drying – Air Replacement

• Once the air in an enclosed space is saturated with solvent vapour, further evaporation of solvent is not possible

• If solvent is retained in the coating film, the drying reaction may be retarded. However the reaction does not stop completely

• If the drying reaction proceeds too long with trapped solvent in the film, the dried film will be porous and spongy

• A porous and spongy film will have reduced mechanical properties


Factors affecting Drying – Air Movement

• Good air movement is essential to prevent the localised build-up of solvent vapour

• Essential for good drying and strong film formation

• Critical for Water based products


Factors affecting Drying – Film thickness

Film thickness has a dramatic effect on drying

Doubling the film thickness from 125 to 250 microns doubles the drying time

For an epoxy deck coating:

Film Thickness Touch Dry TimeHard Dry Time

120 microns 2.75 hours 15 hours

140 microns 3 hours 17.5 hours

210 microns 6 hours 27 hours


Large scale manufacture

• As one of the largest paint manufacturers, we make our paint on a large scale

• At Felling, we manufacture:• 500 000 LT/week• 28 000 000 LT/year

for the marine business


Felling Site

Raw Material Storage

Manufacturing

Warehousing


Raw Material Storage

10,000 lt. solvent tanks Palletized pigments

0.5 and 1 tonne bags of powder/

resins


High Speed Dispersers

High Speed Dispersion Machines – 4,500 to 9,000lt Capacity


Large Scale Paint Manufacture

Let down tanks – 12,000 to 10,000 LT

Charging of powder and dispersion in progress



Bottom of let down tanks and filling pipe-work

Extensive Quality Assurance checks prior to and after filling



20 lt. Antifouling filling line Auto. computer controlled filling Auto. Sealing and labeling

Auto. Stacking palletizing Auto. Filling/labeling of 2.5 and 5 lt cans


Questions?

1.1 Introduction to Paint Technology

Documents

Transcript of 1.1 Introduction to Paint Technology