Nowadays, people pay attention to low carbon and environmental protection, so when decorating, most people will choose some more environmentally friendly coatings. Today mainly talk about environmentally friendly waterproof coatings. Waterproof coatings are mainly divided into two forms of coatings: water-soluble coatings (water-based coatings) and solvent-based coatings. So what is the difference between these two waterproof coatings?
The difference between water-based coatings and solvent-based coatings can be stated from the following perspectives:
A. Differences in coating systems
1. The resin is different. The resin of water-based paint is water-soluble and can be dispersed (dissolved) in water;
2. The diluent (solvent) is different. Water-based paints can be diluted with DIWater (deionized water) in any proportion, while solvent-based paints can only be diluted with organic solvents (odorless kerosene, light white oil, etc.).
B. Different coating construction requirements
1. For the construction environment, the freezing point of water is 0 °C, so water-based coatings cannot be applied below 5 °C, while solvent-based coatings can be applied above -5 °C, but the drying speed will slow down and the interval between tracks will be elongated;
2. For the construction viscosity, the viscosity reduction effect of water is poor, and the water-based paint will be relatively troublesome when it is diluted and reduced in viscosity (the viscosity reduction will greatly reduce the solid content of the paint working fluid, affect the covering power of the paint, and increase the number of construction passes), Solvent-based viscosity adjustment is more convenient, and the viscosity limit will also affect the choice of construction method;
3. For drying and curing, the water-based paint is more delicate, the humidity is high and the temperature is low, it cannot be cured well, and the drying time is prolonged, but if the temperature is heated, the water-based paint also needs to be heated in a gradient, and it will enter a high-temperature environment instantly. After the water-based paint surface dries The overflow of internal water vapor can cause pinholes or even large-scale bubbling, because only water is used as a diluent in the water-based paint, and there is no volatilization gradient. For solvent-based coatings, the diluent is composed of organic solvents with different boiling points, and there are multiple volatilization gradients. Similar phenomena will not occur after flashing (the drying period after the construction is completed to the drying period before entering the oven).
C. Differences in coating decoration after film formation
C-1. Different gloss expression
1. Solvent-based coatings can control the fineness of pigments and fillers according to grinding, and are not easy to thicken during storage. By adding resins to control the coating PVC (pigment-to-base ratio), additives (such as matting agents) to achieve changes in the gloss of the coating film, The gloss can be matte, matte, semi-matte, and high-gloss. The gloss of car paint can be as high as 90% or more;
2. The gloss expression of water-based paints is not as wide as that of oil-based paints, and the high-gloss expression is poor. This is because the water in the water-based paint is used as a diluent. The volatilization characteristics of water make it difficult for water-based paints to express more than 85% high gloss.
C-2. Different color expression
1. Solvent-based coatings have a wide range of pigments and fillers, either inorganic or organic, so various colors can be adjusted, and the color expression is excellent;
2. The selection range of pigments and fillers for water-based paints is small, and most organic pigments cannot be used. Due to the incomplete color tone, it is difficult to adjust the rich colors like solvent-based paints.
D. Storage and Transportation
Water-based paints do not contain flammable organic solvents, and are relatively safe to store and transport. In case of pollution, they can be washed and diluted with a large amount of water. However, water-based paints have temperature requirements for storage and transportation. Milk and other ills.
E. Functional Transcendence
Solvent-based coatings are mostly organic products, and organic products will have a series of problems such as chain scission and carbonization under high temperature conditions. At present, the maximum temperature resistance of organic products does not exceed 400 °C.
Special high-temperature-resistant coatings using special inorganic resins in water-based coatings can withstand temperatures of thousands of degrees. For example, ZS series high-temperature-resistant water-based coatings not only take into account the anti-corrosion and anti-oxidation properties of conventional coatings, but also long-term high temperature resistance, up to 3000 ℃ High temperature, which is impossible for solvent-based coatings.
G. Differences in safety and environmental protection
Solvent-based coatings have potential safety hazards of fire and explosion during production, transportation, storage, and use. Especially in confined spaces, they are more likely to cause suffocation and explosion. At the same time, organic solvents will also cause certain damage to the human body. The most famous case is the case of toluene causing cancer, and toluene is no longer allowed to be used. The VOC of solvent-based coatings is high, and conventional products are even as high as more than 400. Enterprises are under great pressure on environmental protection and safety when producing and using solvent-based coatings.
Water-based coatings are environmentally friendly and safe in production, transportation, storage, and use (except for pseudo-water-based coatings from some informal manufacturers).
Water-based coatings and solvent-based coatings have their own advantages and disadvantages. Because the research on water-based coatings is still immature, the performance of water-based coatings cannot fully meet the needs of social production. The application of solvent-based coatings is still necessary. The actual situation is analyzed and judged, and it cannot be denied because of a certain disadvantage of a certain type of paint. It is believed that with the deepening of scientific research on water-based coatings, one day, environmentally friendly and safe new coatings will be widely used in every corner of the earth.