Solvent, solvent overview

In addition to solvent-free coatings, solvents are important components in various liquid coatings. The solvent has the function of dissolving or dispersing the film-forming substance into a liquid state, reducing the viscosity of the coating, and making it easy to apply and apply. The solvent is very important for the formation and quality of the coating film.

The customary solvent includes a solvent capable of dissolving the film-forming substance, a diluent capable of diluting the solution and a dispersant capable of dispersing the film-forming substance. Some varieties of modern coatings use some compounds that can not only dissolve or disperse film-forming substances, but also chemically react with film-forming substances during the film-forming process to form new substances that remain in the coating film. In principle they also belong to the solvent components and are referred to as reactive solvents or reactive diluents. Solvents in traditional paints are usually volatile liquids, which are customarily called volatiles. Water, inorganic compounds and organic compounds can all be used as solvents, among which there are the most varieties of , such as aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, esters, ethers, ketones, chlorinated hydrocarbons, etc., which are called organic solvents.

In general liquid coatings, the content of solvent is quite large. In thermoplastic coatings, it is generally about 50% or even more than 50% (volume ratio); in thermosetting coatings, it accounts for 30% to 50% . Some solvents are added during paint production, and some are added during construction. The latter are often called thinners or thinners.

The solvent contained in some coatings is a single solvent type, and some coatings use multiple solvent types. In addition to considering solubility, the selection of solvent should also take into account various factors such as volatilization rate, flash point, and boiling point. Organic solvents cause environmental pollution and waste of resources in the production of coatings, especially in construction, which is a problem that needs to be solved in the development of coatings .