Choosing the right paint is often a big problem. And it’s not just about colour, but also about the type of paint and its quality. In the maze of information, it is difficult to find the most valuable answers. The key to success is to start learning about the subject from the very beginning, i.e. from the information on what paint actually is.
Paint is a mixture that produces a coloured coating on any surface on which it is applied. It consists of solvents, pigments and fillers, polymeric binders and additives such as dispersants, thickeners, defoamers and other functional additives.
Each paint ingredient affects the properties of the finished product. Therefore, it is worth knowing what function each of them performs in order to be able to evaluate the quality of the composition and choose the paint that has the best parameters in relation to the price. The most important ingredients that we can find in paints are:
• pigments – they are responsible for the colour of the paint and its saturation. Depending on the chemical structure, inorganic or organic pigments can be distinguished.
• fillers, as the name suggests, fill in the ’empty space’ in the paint, ensuring an adequate amount of dry content in the product. Their unquestionable advantage is their low price, but they can also improve other parameters, such as opacity and resistance to scrubbing.
• polymeric binders – they form a homogeneous film, ensuring that the paint adheres to a given substrate. In addition, they increase resistance to mechanical and chemical factors.
• functional substances – they allow to modify and improve the properties of finished products. These are usually dispersants and thickeners which enable obtaining a homogeneous and stable product.
Solvents are also used in the production of paints. These can be organic liquids or water, which is the base of waterborne paints. Such paints are also called dispersion paints, in which solids are dispersed in water. This means that the dispersed phase (pigments, fillers, film-forming polymer) is suspended in water in the form of single particles that are separated from each other by solvent molecules. The stabilization of this system is ensured by surfactants.
It is also worth mentioning that one of the most important components of the paint, i.e. the film-forming binder, is a dispersion of a specific polymer in water. It is obtained in the process of emulsion polymerization, in which surfactants play an important role. These agents enable effective emulsification of the monomer in water, creating the areas where the polymerization reaction takes place. In addition, they stabilize the polymer molecules formed, giving stability to the entire dispersion. Systems of anionic and non-ionic surfactants are most often used in emulsion polymerization. The most commonly used binders include b. These binders are selected depending on the requirements of the final paint composition, i.e. price, gloss, resistance to abrasion, atmospheric conditions and UV radiation, etc.
The advantages of waterborne preparations over paints containing organic solvents are:
• easier application,
• shorter drying time,
• no unpleasant odour,
• no negative impact on the environment.
An additional advantage of waterborne paints is their compatibility with gypsum, concrete, plaster, brick, wood and plastic substrates. However, they are not suitable for covering limestone objects and plasters containing a lot of lime. Dispersion paints are suitable for painting both indoor and outdoor surfaces. They are characterized by high durability and abrasion resistance, and at the same time they are very efficient.
Waterborne dispersion paints are also known as emulsion paints and latex paints. Each of them is a dispersion system and in fact all of them could be categorized in this way, yet they appear under different names. Why is this the case?
The emulsion is a variant of dispersion in which both the dispersed phase and dispersion medium are liquids – liquid resin and water. Emulsion paints, among other types of coatings, are perceived as products for use in less demanding rooms, usually inside the buildings. Therefore, in everyday language, emulsion paint means a lower quality product.
It is similar with latex paints. They are often seen as high-quality products, resistant to various factors. In reality, however, the word latex is synonymous with the word dispersion. These terms are commonly used interchangeably in America. This is due to differences in the translation and origin of words. It is confirmed by the provision included in the terms and definitions of lacquer products with the symbol PN-EN 971-1. It contains the phrase “dispersion paint (emulsion paint, latex paint)”.
The paint quality is confirmed by the content of binder and pigments in the product. The higher the content of these ingredients, the better the product. A lower paint grade can be identified by high filler content and low pigmentation. Such a preparation is characterized by poor coverage, and thus the need to apply several layers of paint on the surface. As a result, it may turn out that cheaper paint of lower quality will be a more expensive solution due to low efficiency.