Reducing the amount of volatile organic substances (VOC, or volatile organic compounds) is a topic that is frequently discussed nowadays, mainly because national regulations are now urging more and more to lower the levels of VOC in most paints and coatings.
Owing to these greater restrictions, it is now more important to know what comprises different kinds of sealers, because they may contain a VOC anywhere from lower than 100 g/L (very low) to higher than 400 g/L (very high). Knowing the VOC helps you find out the type of sealer that suits your project best.
There are two variants of concrete (stone) sealers: water-based sealers with usually low VOC, and solvent-based sealers with usually high VOC. Both used in concrete coatings; they can act both as decoration and protection. After the concrete is cured, usually 21-28 days, these sealers are applied. Their decorative functions can make the concrete glossier as well as to enhance colour, thus improving aesthetic quality. Their protective functions are to shield the concrete from damage as well as provide greater resistance to chemicals and stains.
Most film forming concrete sealers that are resistant to ultraviolet (UV) rays are 100%-based on acrylic polymers. Technological improvements now provide contractors with an opportunity to choose between different types of high-grade acrylic sealers that use water-based or solvent-based polymers. Both of them act to seal concrete with a continuous coat.
In a sealer that’s water-based, the particles comprising the polymer are scattered in water. After application of the sealer to the concrete, the water evaporates and the particles comprising the polymer begin gathering together. After more evaporation, the particles deform and then bind together...the result being a coating that’s continuous and clear.
In a sealer that’s solvent-based, however, the particles of the polymers are not dispersed. Instead, the polymer forms a clear and continuous solution with the solvent. As the solvent evaporates, the chains comprising the polymer are brought closer, and in time, they interlock firmly. Both solvent-based and water-based topical sealers stick to the surface of the concrete where they are applied; that is why upon application, eventually the surface of the concrete will look glossy.
For your projects, if you want to consider using water-based sealers, you should remember that both types of sealers (water-based and solvent-based) work in nearly the same way. Here are the similarities:
Strong And Long-Lasting. These are the most important attributes of any sealer; a sealer must function in protecting the surface. High-quality topical acrylic sealers can protect anywhere between 2-5 years outdoors. Both water and solvent based sealers also protect concrete from stains such as car stains, spills from food or drink, and chemicals – it is possible to remove these stains before they become permanent.
Can Be Applied Easily. Both types of sealers can be bought in ready-made, ready-to-apply mixtures. Depending on where they will be used, these sealers are often rolled-on or sprayed on concrete.
Resistance To Ultraviolet Light. Ultraviolet light can pass through 100%-acrylic sealers easily, so they won’t decompose compared to polymers, like nonaliphatic polyurethanes, styrene-based acrylics, and some types of epoxies, that absorb UV rays. Resistance to UV rays can result in protection for a longer period.
While water-based and solvent-based sealers have similarities, they also have variant differences, such as:
How They Look. This is a major difference between the two types of sealers. Sealers that are water-based look milky white upon application. This is because scattered polymer particles reflect visible light in a different way than the way water reflects visible light. The finish can be semi-gloss and matte. Sealers that are solvent-based on the other hand, are good in wetting out and penetrating surfaces of concrete, so the finish is glossy and the colour of the concrete underneath is intensified. The one drawback is generally the intense “wet look” of a cheap inferior solvent sealer can disappear quite quickly!
How They Are Handled. Water-based sealers do not burn, have no intoxicating smells typical of solvents and can be cleaned up easily and quickly after application. Saved time by busy contractors could spell the distinction between arriving on the job early and arriving home late.
Both types of sealers, however, do not differ much in their protective properties, and both can protect concrete surfaces extremely well. If you want a sealer with a low VOC, go for a water-based sealer; for it is strong and durable and you can work with it easily. Also bear in mind that washing up is also much easier when compared to a solvent!