Differences between water-based coatings and solvent based coatings

The differences between water-based coatings and solvent based coatings can be compared from the following aspects: different resins of coating systems are different: the resins of water-based coatings are water-soluble and can be dispersed (dissolved) in water; Diluents (solvents) are different: water-based coatings can be diluted with diwater (deionized water) in any proportion, while solvent based coatings can only be diluted with organic solvents (odorless kerosene, light white oil, etc.).

Different construction environments are required for coating construction: the freezing point of water is 0 ℃, so water-based coatings cannot be constructed below 5 ℃, while solvent based coatings can be constructed above -5 ℃, but the drying speed will slow down and the interval between lanes will be lengthened; Construction viscosity: the viscosity reduction effect of water is poor, and the water-based coating will be relatively troublesome when thinning and viscosity reduction (the reduction of viscosity will greatly reduce the solid content of the coating working fluid, affect the covering power of the coating, and increase the number of construction passes). The solvent based viscosity adjustment is more convenient, and the viscosity limit will also affect the choice of construction methods; Drying and curing: the water-based paint is more delicate. It cannot be cured well when the humidity is high and the temperature is low, and the drying time is prolonged. However, if the temperature is raised and heated, the water-based paint also needs gradient heating, and instantly enters the high-temperature environment. After the surface of the water-based paint dries, the internal water vapor overflow will cause pinholes and even large area bubbles, because there is only water in the water-based paint as a diluent, and there is no evaporation gradient.

For solvent based coatings, the diluent is composed of organic solvents with different boiling points, and there are multiple volatilization gradients. After flashing (the drying period from the completion of construction to entering the oven), it will not appear similar phenomenon when it is baked in the high-temperature area. Different gloss expressiveness of film decoration after film formation: solvent based coatings can control the fineness of pigments and fillers according to grinding, and it is not easy to coarsen in storage. The change of film gloss can be achieved by adding resin to control the coating PVC (yen base ratio) and additives (such as matting agent). The gloss can be matte, matte, semi matte and high gloss.

The gloss of automotive paint can reach more than 90%; The gloss expressiveness of water-based coatings is not as wide as that of oil-based coatings, and the high gloss expressiveness is poor. This is because the water in the water-based coatings is used as a diluent. The volatile characteristics of water make it difficult for the water-based coatings to show more than 85% high gloss. Different color expressiveness: solvent based coatings have a wide range of pigments and fillers, which can be inorganic or organic, so they can call up various colors, and the color expressiveness is very good; The selection range of pigments and fillers for water-based coatings is small, and most organic pigments cannot be used. Due to incomplete hues, it is difficult to produce colors as rich as solvent based coatings.