COATINGS TO PROTECT CONCRETE FLOORS & STRUCTURES FROM CHEMICAL ATTACK
Many people have a basic understanding of what a chemical resistant coating is. It may mean a paint system that is applied to a surface to protect from attack by an aggressive substance. Or it may be a decorative floor coating which must retain its characteristics under various degrees of chemical exposure.
Air drying one component coatings do not generally provide good protection against chemical attack. In the main these types rely on evaporation of water or solvent to leave a resin film and produce poorly chemical resistant coatings. An exception to these are one component polyurethanes which react with air borne moisture and so could be considered as a two component system.
Two component reactive systems offer greater chemical resistant coatings. Epoxy, polyurethane, methacrylate, and vinyl esters resins are commonly recognised and these contain various binder groups relying on a process of cross-linking or knitting together of molecular strands to form their structure. The degree and density of the cross-linking within a group determines in part the hardness and chemical resistance of that group. However within the binder groups of, say, epoxy resins a variety of characteristics occur, further affecting chemical resistance.
So what are the factors affecting performance and which systems perform best?
The ability of a chemical resistant coating to protect against a corrosive medium depends on;
A given resin type may be totally resistant to a concentrated chemical at a low temperature but may disintegrate when exposed to a more dilute concentration of the same chemical at a higher temperature.
Therefore all factors must be considered when selecting a chemical resistant coating.
Generally the following resin types offer resistance against various chemicals.
Commonly used to produce durable floor coatings and screeds they have resistance to aqueous acids and alkalis, fats, oils, general fuels, lubricants, salt and sugar solutions. They are susceptible at higher temperatures.
Resucoat HB solvent free high specification epoxy resin coating giving excellent chemical resistance. Perfect for floors in manufacturing and food industries.
Resutop LV specifically designed floor coating for aircraft hangars. Excellent resistance to aggressive SKYDROL hydraulic fluids and oils.
Nitocote EP405 a solvent free epoxy resin coating for potable water retaining structures. Highly chemical resistant, high gloss and easy to clean.
Nitocote EP410 highly chemical resistant two pack epoxy system. Provides protection to concrete and steel in aggressive immersion conditions. Particularly suitable in process and sewerage plants.
Nitocote EP403 a damp tolerant chemical corrosion and abrasion resistant coating for sewage works marine environments and tunnels.
Sikagard 63N an abrasion resistant, universal coating for normal to highly aggressive chemical environments.
Commonly used to produce durable floor coatings and screeds they have resistance to organic acids and alkalis, fuel and hydraulic oils, and aromatic and aliphatic solvents. They also have greater resistance than epoxy resins at elevated temperatures and in screed form to allow steam cleaning.
Resutile a high grade, two-pack, hard wearing polyurethane floor coating designed for maximum chemical resistance it is also light-fast and flexible. Resutile has good resistance to impact abrasion and heavy traffic. The system is resistant to high temperatures up to 150'C.
Resudeck a two-pack, high build, hard wearing polyurethane floor coating which forms a tough and durable finish with resistance to light-medium chemical attack it can also be used in wet environments. Solvent-free coating with a 100% solids content, which cures to a gloss finish. Resistant to hot water and can be steam cleaned.
Resupen a system comprising of a range of high grade polyurethane resin coatings designed to seal concrete in depth in either clear or coloured decorative finishes.
Used as durable coatings offering good resistance to aqueous solution but can be poor against solvents of all types. Can be modified for use where cold conditions prevail.
Used mainly for bund and tank lining offering excellent chemical resistance for almost all chemicals. They do, however require specialist expertise in application.
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