What is dewaxing solvent

As the paint on the wall dries, the solvent evaporates. Photo: Pixabay

What do paints, varnishes, wood preservatives and adhesives have in common? Among other things: They are liquid at the time of processing and then harden. All of these products - and many more - also contain solvents. These are the substances that evaporate during the drying process. In doing so, they often give off unpleasant odors. The extent to which this can be harmful depends on the type of solvent used.

Paints such as paints, varnishes or wood preservatives ultimately have the purpose of creating a visually appealing and / or protective coating. The products only fulfill this function after they have hardened, i.e. when they have become solids.

The same goes for adhesives. In the construction sector, these are not only used to glue building materials together, but are also part of the binding agents within building materials. The adhesive function also only unfolds when it is dry. However, in order for paints and adhesives to be processed at all, they must first be liquid. To do this, they are dissolved in a liquid: the solvent.

general definition

A solvent (often also called “solvent”) is a general term used to describe a liquid that is able to dissolve other substances without causing a chemical reaction between the solvent and the dissolved substance. Solids are usually dissolved, i.e. the components that make up a paint or an adhesive, for example. However, some solvents are also able to dissolve other liquids or gases.

Due to the solvent, the dissolved substance becomes liquid and can thus be processed better. The fact that there is no chemical reaction between the solvent and the dissolved substance is a prerequisite for the solvent to be able to evaporate again later and for the previously dissolved substance to remain in unchanged form.

By the way, the best known and most common solvent is water. Many paints and adhesives are also water-based these days. There are also solvents that contain organic compounds. In this context, products that give off so-called volatile organic compounds (“volatile organic compounds” = VOC) are considered to be particularly hazardous to health in this context.

Water and oils as solvents

Water-based paints and adhesives are usually described by manufacturers as "solvent-free". The same applies to products that contain natural oils as solvents - for example natural colors. Strictly speaking, this is wrong, because the products mentioned also contain solvents - water or oil.

But the word solvent has a negative connotation in public because most of them only think of products that emit VOC pollutants such as formaldehyde. For the average consumer, the equation solvent = pollutants applies. In this respect, one cannot blame industry for speaking of being solvent-free when water or natural oils are used as solvents.

Restricted definition

Adhesives usually also contain solvents. Photo: Pixabay

The industry can also justify its marketing message that water- and oil-based products are solvent-free with the Technical Rules for Hazardous Substances (TRGS). The TRGS 610 contains a much more restricted definition of the term solvent than the general definition mentioned above. Accordingly, solvents are “volatile organic substances and their mixtures with a boiling point of ≤ 200 ° C, which are liquid under normal conditions (20 ° C and 101.3 kPa) and are used to dissolve or dilute other substances without chemically dissolving them change".

The TRGS are published by the Federal Ministry of Labor and Social Affairs and reflect the status of the safety, occupational medical, hygienic and ergonomic requirements for hazardous substances with regard to their placing on the market and handling.

"Solvent-free" = healthy living?

On the other hand, it would be a mistake to assume that water- or oil-based (“solvent-free”) paints automatically stand for healthy living. For example, water-based interior paints also usually contain small amounts of volatile organic compounds. Most of all, however, they contain preservatives and thickeners. These are supposed to compensate for the disadvantages of water as a solvent. Preservatives are biocides that switch off microorganisms, primarily to prevent the formation of mold. These components also evaporate over time and thus get into the room air.

Even natural colors cannot be generally described as healthy. For example, many of these products contain orange oil as a solvent. This is of course not toxic in itself, but there are also people who are allergic to this or other essential oils.

VOC in solvents

Paints and adhesives that are not labeled as solvent-free usually contain the classic, VOC-containing solvents. The VOC group comprises a total of around 200 organic, i.e. carbon-containing individual substances that evaporate very quickly.

Otherwise they have very different properties. In addition to the aldehydes, terpenes and many ketones, esters, alkanes, aromatics and halogenated hydrocarbons are also part of the VOC substances. Not all VOCs are harmful to human health. Terpenes, for example, are not dangerous in principle. They also occur naturally in wood, where they provide the typical smell of the natural material. Nevertheless, there are people who are allergic to terpenes.

Many other VOCs, which are also found in paints and adhesives, are, however, to be assessed much more critically. They can irritate mucous membranes and cause headaches. Worse still: some VOCs are also suspected of causing functional disorders in the liver and kidneys, damaging the nervous system and causing cancer in the long term.


About the author Roland Grimm has been a freelance journalist based in Essen since February 2013 and regularly writes specialist articles for Building material knowledge. Before that, he was a specialist editor at the industry magazine for around six years Building materials market and also editor-in-chief and, from 2010, editor-in-chief of the trade journal building materials practice. Contact: freelance [email protected]

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