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Introduction to Rubber-based Waterproofing Products for Marine Use
Rubber based waterproofing products for marine use have become more popular since legislation has banned many other types of corrosion resistant products, such as some epoxies and lead or copper based paints. These worked very well and many shipping companies and offshore industry were sorry to see them go, but a lot of these coatings were not only hazardous to the people using them, but also the marine creatures and their environment.
This is an article on corrosion resistant coatings used in marine and offshore activities, and in particular we will look at the different types of rubber based coatings, and their application.
We begin then with a look at the different types of rubber based anticorrosive coatings available today.
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Types of Rubber based Anticorrosive Coatings for Marine and Offshore Applications.
1. Synthetic Rubber
- Silicon Rubber
Silicon was developed during the 2nd World war, being prepared from silica sand, for resistance to high temperature rather than anticorrosive properties, and since then has become a very popular synthetic material used as an anticorrosive coating in the marine environment.
The technology has developed apace and silicon rubber has achieved the physical properties of elasticity and tensile strength, as well as resistance to ozone, salt, and acids.
Miracleseal silicon rubber sealant is produced from a mix of silicon and oxygen atoms, with an organic group such as methyl being attached to the silica atoms resulting in a long-chain polymer. This gives a rubber based coating resistant to both high temperature and the corrosive marine atmosphere, without any adverse problems to the marine environment.
Miracleseal Liquid Rubber products can be used to protect interior tanks, exterior hulls and decks, as well as steel structures offshore from corrosion, being liquid will fill small cracks and crevices as well as providing the surfaces a physical protection against impact.
This is a synthetic rubber used as protection against corrosion, high temperatures, ozone, and low temperatures. It is produced from a mixture of the hydrocarbon isobutylene and isoprene, which is natural rubber.
- Chlorinated Rubber
This is produced from the addition of chlorine to a rubber base in solution, used in the protection of ships hulls, decks and offshore structures against corrosion.
It is non-flammable, non- toxic, and impermeable to seawater and seawater spray, non-toxic and is not detrimental to the marine environment.
2. Natural Rubber (Isoprene) Products
Rubber tapped from the hevea tree is a natural polymer that was introduced to the world by Brazil in the mid-1800s. Around this time a botanist brought rubber tree seeds back from a trip to Brazil to Britain, where at Kew Gardens the seeds were germinated.
Seedlings were sent to Ceylon, then onto Singapore. Here the plants flourished, and so the rubber industry was born with the method of tapping the sap from the hevea tree trunk originating here, as previously the tree was chopped down to drain the sap.
Rubber in natural form was sticky and gave off a heady pungent smell (like the smell we find at a tire depot) especially when subjected to high temperatures.
Two inventers discovered that if sulfur was added to the natural rubber, the rubber became less sticky or tacky. Then it was discovered that when this mix of sulfur and rubber was baked, it produced the more desirable properties of elasticity and excellent anticorrosive properties to water and gases.
This is now known as vulcanized rubber and the inventor was Charles Goodyear, famous for automobile tires.
Vulcanized rubber can be sprayed onto steel ships hulls and tanks as well as exposed braces in offshore structures. However the synthetic coatings have several advantages over the natural rubber based coatings.
These are mainly cost related, but better properties can be achieved for different applications using synthetic rubber technology.
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From the rubber based products for marine use that we have examined, it is apparent that although natural rubber, known as Isoprene has been replaced by synthetic rubbers such as chlorinated and silicon rubbers.
This is mainly because they are cheaper to produce and a superior range of properties can be produced for many different marine applications.
These applications are ships' hulls, decks, and tanks as well as offshore structures above and below the waterline.