Protect any surface from harsh substances with chemical resistant coating
Nearly all coatings will be exposed to chemicals at some point, whether cleaning products, spills, or fumes. However most of these are mild, and the coating does not need a special formulation. Chemical resistant coatings or paints are designed to provide protection from the harshest of substances. They need to perform safely and consistently under punishing conditions, and so need to be highly resistant. Without proper chemical resistant coating, solvents, acids, alkalis, salts, and other substances can be absorbed by the substrate, causing deterioration and contamination.
The right chemical resistant coating is the one that satisfies the requirements of the chemical, as well as the needs of the substrate. Choosing correctly requires fully understanding both. In this article we will outline the different chemical resistant coatings options, and provide a guide for choosing the right one as well as where to find products and contractors in South Africa.
Factors that affect the choice of chemical resistant paint
Substrates and environments which require heavy duty protection from chemicals include flooring, storage or holding tanks, pipelines, bunds, buried metal and concrete structures, treatment plants, laboratories, cooling towers, factories, machinery and equipment, just to name a few. Whether you need an acid resistant paint, chemical tank lining, fuel resistant paint, or a chemical resistant paint for steel or wood, you need to know the requirements of the coating first.
The range of substrates, environments, and chemicals is matched by the range of chemical resistant coatings. To choose the right chemical resistant coating you need to know:
- The type & concentration of chemical
- The temperature of the chemical
- The degree of exposure to the chemical
- The duration of the exposure
The 4 types of chemical resistant coating for different purposes
Chemical resistant coatings are available in a wide range of formulations, suited to different applications. The main types are polyurethane, epoxy, phenolic, and fluoropolymers. The choice of coating is further complicated by extra requirements such as high corrosion resistance, or sufficient lack of friction.
1. Epoxy chemical resistance coatings
Protection against acids, alkalis, solvents, caustic fluids, fuels, fatty acids, salt or sugar solutions, chemical cleaning detergents and more
Uses: An unprotected concrete floor can quickly deteriorate through exposure to chemicals, particularly flooring in the food and drink industry, garages, factories, and plants. Applying a coating that can withstand these exposures is important to prevent bacterial contamination. Epoxy coating is suitable for metals, concrete and wood.
Disadvantages: The drawback with epoxy chemical coatings is a tendency to weaken with high or fluctuating temperatures, and it is not as flexible as polyurethane. They are also not good with UV radiation (which causes it to chalk and fade), and can be stained by chemical attack.
2. PU resin based coatings
Resistant to organic caustic fluids, acids and alkalis, fuel and hydraulic oils, and solvents
Uses: Where greater flexibility and an ability to deal with high temperatures is needed, polyurethane is the traditional alternative to epoxy. Polyurethane is also the preferred choice of chemical resistant coatings in the dairy industry where there is exposure to lactic acids.
Disadvantages: Softer than epoxy coatings, polyurethanes are more likely to abrade. Extremely sensitive to humidity at application. In general less resistant chemical coatings than epoxies.
3. Phenolic epoxy and PU coatings
Resist 98% sulphuric acid, hydrochloric acid, transmission fluid, gasoline, formaldehyde, phenol, and numerous other chemicals
Uses: Protective chemical coatings for tanks, ducts, piping, immersion service for most acids, solvents, and salts (chemical storage). Applicable for flooring in healthcare, science, technology and electronics industries, as well as chemical and waste treatment plants, pulp and paper mills, and power generation plants.
Disadvantages: Not recommended for exposure to some strong organic acids and solvents, and the less epoxy used in the makeup of the coating, the less resistant to chemicals it is.
4. Fluoropolymer coatings
Resistant to a wide range of chemicals, including concentrated sulphuric, nitric, hydrochloric and phosphoric acids in temperatures up to 300°C
Uses: Normally used where a low coefficient of friction or a lubricious surface is required. Suitable as chemical resistant coatings for use on concrete or metal in secondary containment linings, acid plants, fertiliser plants, oil refineries, and more.
Disadvantages: Fluoropolymers have poor weather protection characteristics, and cannot withstand acetone, esters, ketones, and acetic acid.
Chemical resistant coatings in South Africa – Products from top manufacturers
With so many different environments and surfaces that require chemical resistant coatings, it is no surprise that the range of products and services is extensive. There are the chemical coatings above, but there are also specially formulated coatings like methacrylate, which cures at low temperatures and is used for cold-store and freezer rooms. Below is a table outlining some of the available products, with price indications (subject to change and variation). It is these chemical coatings from reputable coatings manufacturers like AkzoNobel that installers trust.
|Chemical resistant coating type||Chemical resistant coatings product||Product suitability|
|Two component epoxy||Jotun Jotafloor Topcoat||Ideal for industrial floors, laboratories, hospitals, food and beverage plants, kitchens, warehouses, factories, and manufacturing facilities.|
|Two component polyurethane topcoat||Rust-Oleum 9600 Rust-O-Thane Polyurethane||Heavy industrial and marine exposures, moist conditions and high abrasion and impact situations. Especially recommended for weather resistance.|
|Two component epoxy phenolic||International Interline 850||Tank and pipe lining for steel storage tanks and pipes containing a range of products including crude oil, gasoline, caustic solutions, potable water, and solvents.|
|Two component epoxy novolac||Sherwin-Williams Nova-Plate 325||For use on steel and masonry surfaces in industrial and marine environments such as oil storage tanks, secondary containment, ethanol storage tanks, and more.|
|Two component novolac vinyl ester||International Interline 955||Reinforced with glass flake to increase chemical and abrasion resistance. Intended for use in internal lining of chemical storage tanks and vessels for hot media (up to 90°C) or acids.|
South African chemical resistant coating applicators
A chemical resistant coating should be applied by a trained professional to ensure an effective and flawless application. Fortunately there are many coating installer companies operating across South Africa. If you have a project that needs chemical resistant coating, our experts are here to help! In cooperation with our partners we can provide you with a tailor-made quote, and connect you with the right coating solution. Just get in touch via e-mail or the “Request a quote” button at the bottom of this article.
Here is a selection of South African companies specialised in applying chemical resistant coatings.
|Chemical resistant coating specialist||Address|
|Nordbak||Immelman Road, Wadeville, Germiston, 1422|
|StonCor Southern Africa||8 Cresset Road, Midrand Industrial Park|
|Flowcrete SA (Pty) Ltd||176 Voortrekker Street, Jacobs, Durban 4052|