When people buy paints and coatings, they usually have thinners as matching paints and coatings. , many people don’t know what diluent is? Today we will learn what diluent is and the correct selection and use of diluent. Generally speaking, thinners are volatile liquids used to dissolve and dilute paint. Can be used to adjust the viscosity of paint to suit coating requirements. Thinner usually consists of two parts: solvent and diluent, and sometimes a part of co-solvent is also added. Substances that can dissolve other substances are called solvents.
The solvents used in coatings are mainly various organic liquids that can dissolve film-forming substances such as grease, paint, resin, and cellulose. They are the main component of the diluent. The co-solvent itself does not have the ability to dissolve film-forming substances. Mixing it with a certain solvent in an appropriate proportion can enhance the solvent's dissolving ability. Only the solvents used in some coating products (such as nitrocellulose paint, etc.) require the addition of cosolvents. Although diluent cannot dissolve film-forming substances, it can be used together with the solvent of the coating without causing harmful effects. The main purpose of applying diluent is to adjust the evaporation rate of the diluent and reduce its cost.
Solvent, co-solvent and diluent are not absolute. The same organic substance can be a solvent for one type of paint, but a co-solvent for another type of paint. or diluent. Therefore, they are often collectively referred to as organic solvents, and the diluent is actually just a mixed solvent. For a specific variety, it is important that the proportion of solvents, diluents and co-solvents in its composition should be appropriate. What is particularly important is the type and dosage of solvents and diluents used in the coating. Only in this way can the formula be prepared. Best thinner for paint.
When preparing diluent, due to various The solubility and evaporation speed of organic solvents vary greatly, so they must be formulated according to the composition and performance of various types of coatings and by applying solvent theory (polar similarity principle, solvation effect, solubility parameter principle).
Therefore, different paint packages have different Thinner, the same kind of paint, has different compositions due to different seasonal climates. For example, in summer, the paint thinner is adjusted to dry more slowly, while in winter, the paint thinner is adjusted to be slightly faster drying. Therefore, summer thinner products should not be used in winter, otherwise, they will cause paint film problems such as bottom biting due to slow drying.
There are many inferior dilution products on the market. Although the price is low, the ingredients are different, the odor is highly toxic, the volatilization speed is too fast, and the solubility is extremely poor, which not only seriously affects the health of construction workers, but also easily causes the following paint film pathologies:
①Poor hiding power: The film thickness is too thin and the paint film penetrates The color of the underlying surface can be seen.
②Lost: Lacquer The film has a full gloss before drying, but lacks gloss after drying or the gloss of the paint film gradually disappears in the future.
③Orange peel: The surface of the paint film is uneven , similar in appearance to orange peel and grapefruit peel.
④Clouds/spots (silver paint Small spots): The color of the silver paint changes, forming patches of dark or light color spots, often forming stripes of different colors along the direction of the spray paint.
⑤Pinholes (potholes): Paint After painting, due to the rapid evaporation of the diluent, the paint liquid has no time to replenish, resulting in pinhole-like holes or phenomena like leather pores.
⑥ Prickly heat (solvent bubbles): due to The thinner evaporates too quickly, and water vapor penetrates into the paint film, causing small bubbles and bubble marks in the topcoat.
⑦Blurry/fogging: Paint film surface Appears as a milky white mist.
⑧Drip, droop, and tear: During the drying process of the paint, excess paint on the vertical surface causes sagging from top to bottom or the lower edge of the paint film. The phenomenon of thickening.
Therefore, choose and use regular manufacturers correctly The matching thinner can not only make the paint film have a good appearance, but also because its evaporation speed matches the paint, it can ensure the appearance of the paint film after painting, while avoiding some disadvantages caused by construction.
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