Future development trend of green paint

Because traditional coatings have an impact on the environment and human health, people are now thinking of ways to develop green coatings. The so-called "green coatings" refer to energy-saving, low-pollution water-based coatings, powder coatings, and high solids coatings (or solvent-free coatings ) And radiation curing coatings. Before the 1970s, almost all coatings were solvent-based. Since the 1970s, due to the high cost of solvents and the increasingly stringent requirements for reducing VOC emissions, more and more coatings with low organic solvent content and containing no organic solvents have been greatly developed. Now more and more green paints are used. The following new paints are currently well developed paints.

1. Solid content solvent-based paint. The high solid content solvent type is developed on the basis of common solvent type coatings in order to adapt to the increasingly strict environmental protection requirements. Its main feature is to reduce the amount of organic solvent and increase the solid component under the premise that the original production method and coating process can be used. This type of coating was developed in the United States as the center since the early 1980s. Normal low-solids solvent-based coatings have a solids content of 30% to 50%, while high-solids solvent-based (HSSC) requires solids to reach 65% to 85% to meet increasingly stringent VOC limits. In the formulation process, using some solvents that are not listed as VOCs as a diluent is a modification of the strict VOC limits, such as acetone. A small amount of acetone can significantly reduce the viscosity, but because the acetone volatilizes too quickly, it will cause a potential fire and explosion hazard, which needs to be strictly controlled.

2. Water-based paint. Water is different from most organic solvents in that it is non-toxic, odorless and non-flammable. Introducing water into the coating can not only reduce the cost of the coating and the fire caused by the presence of organic solvents during construction, but also greatly reduce VOC. . Therefore, water-based coatings have made great progress and development since its inception. The China Environmental Labeling Certification Committee issued the "Technical Requirements for Waterborne Coatings Environmental Labeling Products", which stipulates that: the content of volatile organic compounds in the product should be less than 250g / L; during the production process of the product, no artificial compounds containing heavy metals should be added, and the total content of heavy metals Less than 500mg / kg (in terms of lead); formaldehyde and polymers should not be added artificially during the production process, and the content should be less than 500mg / kg. In fact, water-based coatings now account for about half of all coatings. Water-based coatings mainly have three types: water-soluble, water-dispersible and latex.

3. Dust coating. Dust paint is a relatively advanced paint in China. Dust coatings are theoretically absolute zero-VOC coatings, with their unique advantages. Perhaps after completely abandoning VOCs in the future, dust coatings are one of the most important directions for the development of coatings. However, its application limitations require more extensive and in-depth research. For example, its manufacturing process is relatively complicated, the manufacturing cost of the coating is high, and the baking temperature of the dust coating is much higher than that of the general coating, and it is difficult to obtain a thin coating. Poor color matching, poor uniformity of irregular objects, etc. These need to be further improved, but it is one of the future development directions.

4. Liquid solvent-free paint. Liquid solvent-free coatings that do not contain organic solvents include two-component type, energy beam curing type, etc. The latest development trend of liquid solvent-free coatings is the development of single-liquid type liquid-free coatings that can be constructed by ordinary painting and spraying processes.

The research and development direction of coatings is becoming more and more clear. It is to seek coatings whose VOCs are continuously reduced to zero, and the range of use should be as wide as possible, the performance is excellent, and the equipment investment is appropriate. Therefore, water-based coatings, powder coatings, solvent-free coatings, etc. may become the main direction of future coatings development.