Water-based coatings are one of the trends in future development. Compared with traditional solvent-based coatings, water-based coatings have obvious deficiencies in adhesion to substrates, wear resistance, solvent resistance, and hydrolysis resistance. By utilizing the three-dimensional cross-linking effect of the cross-linking agent, the above deficiencies can be effectively improved.
Common crosslinking agents include aziridine, isocyanate, and polycarbodiimide. Aziridine and isocyanate have the defects of strong volatility and high toxicity, which are not in line with the environmental protection concept of water-based coatings. Polycarbodiimide mostly uses water as emulsifier, which is green, environmentally friendly, safe and non-toxic, and can well improve the crosslinking degree, coating hardness, coating abrasion resistance, and hydrolysis resistance of waterborne coatings such as polyurethane and acrylic ester, the solvent resistance of the coating, the adhesion between the coating and the substrate, etc. With its excellent performance, polycarbodiimide is an ideal crosslinking agent for the configuration of water-based coatings .
Both polyurethane and acrylic ester contain a large number of carboxyl groups, and carbodiimide can react with carboxyl groups in a network-like cross-linking reaction, thereby increasing the molecular weight of the cured coating and improving the overall performance of the coating.
In addition, under normal temperature conditions, the reactivity of polycarbodiimide crosslinking agent emulsion with carboxyl groups is very low, which ensures that the two-component coating still has a long shelf life after configuration, and solves the rapid curing problem of conventional crosslinking agents which leads to short storage time of the prepared solution. However, in the case of heating, as the water in the system is evaporated, the reactivity of the polycarbodiimide and the carboxyl group increases rapidly, and the curing can be completed in a relatively short time.
Longyi New Materials is a professional water-based polycarbodiimide solution provider, with a number of carbodiimide-related patents and mature production, sales, and technical service system. High-quality products have served coatings, automobiles, textiles, and sports materials. If you want to know more cases of water-based carbodiimide crosslinking agents, please contact us: [email protected]
