Common Types of Paints March 15, 2007
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Let me dig up some literature and go through some common types of paint, in a way that does not put you to sleep! However, if it does put you to sleep, drop me a line. I can compile it into a CD for insomniacs 
Lets dive straight in.
Emulsion Paint
This is the stuff we put on our walls. It is made up of monomers, surfactant, initiator and water. Basically, the initiator starts the process, causing the surfactant to emulsify the monomer and prepare it for polymerization.
Emulsion paints are getting confusing to the average consumer. I recall a time when you only have choose the colour. Nowadays, buying paints for your walls requires you to go through what seems like a 20 minutes survey. Would you like your paint to be washable? anti-bacterial? fragrant? odourless? slightly glossy? able to cover hairline cracks? waterproof? It’s easier to sit for an examination than to buy paint. And you haven’t even got to the colours yet!
My next post will explain more about the different types of wall paints.
Alkyd Paints
This is the stuff we put on our wooden doors and metal gates. Alkyd paints are made of oil modified alkyd resins. The drying process is oxidative ie. they dry by reacting with oxygen in the air. Because of this, alkyds should never be applied in thick coats as only the surface will dry. If you get wrinkling, you’ve applied too thick a coat.
Alkyd paints are cheap, easy to apply, and has fairly good weathering properties. It has good recoatability and are widely used as a maintenance paint. It can generally be thinned with turpentines or thinners .
Most alkyd paints in the market are glossy. If you need matt or satin, this can be specially tinted.
Bituminous Paints
These are made up of coal tar pitch or asphaltic bitumin. They are highly water-resistant, cheap and easy to apply on most surfaces. Little surface preparation is necessary. Bituminous paints cannot be overcoated with other types of paints because the tar tends to bleed through whatever sitting on top of it. This paint is commonly used to coat drains and wooden surfaces constantly exposed to the elements. They are black in colour which makes it solely protective, not decorative.
Epoxy Paints
Probably the best heavy duty paints available on the market. They are two-component paints ie. it has a part A ‘base’ and a part B ‘hardener’. The 2 components have to be thoroughly mixed just prior to painting. They therefore dry chemically, not physically. The drying process involves the chemical reaction of the epoxy resin binder with the polyamine or polyamide binder.
When fully cured, this stuff is very tough and can withstand water, chemicals, oils and many types of solvents.
The disadvantages of epoxy paints are that they cure slowly and they tend to lose their gloss rapidly. When exposed to UV, they also have a tendency to chalk.
Epoxy paints are widely used as floor coatings for factories and carparks.
Polyurethane Paints
These are isocyanate-based paints and like epoxy paints, also consists of 2 components. They cure as a result of chemical reaction between the polyester or polyether binder and an isocyanate hardener.
Polyurethane paints are heavy duty paints and are also resistant to water, chemicals and solvents. They are better than epoxy paints in that they retain their gloss better and do not turn chalky when painted exteriorly. However, in terms of hardness, epoxy paints usually come up tops.
Polyurethane paints are widely used in outdoor metal structures such as metal towers, tanks and platforms.
Anti-fouling Paints
These are paints that preventing marine fouling and are usually applied on the underwater hulls of boats and ships. Fouling causes the damage to the ship hull as well as increasing drag. This is significant to ocean-going crafts, where fuel consumption can increase tremendously.
The component that prevents marine fouling is known as the biocide. In the past, there was widespread use of tin for this purpose. Tin-based anti-fouling paints were very common. A few years ago, environmental concerns resulted in a worldwide ban. Nowadays, tin-based anti-fouling paints are almost non-existant. Another biocide commonly used is copper.
This topic will be dealt with in further details in another post under the ‘Marine Paints’ category.
Asleep yet?
