Application Situation and Research Development of Waterborne Container Coatings

The application status and latest research progress of waterborne container coatings at home and abroad were summarized. It points out that as people's awareness of environmental protection continues to increase, and the international community has put forward higher requirements of environmental protection for container coatings. Waterborne container coatings have become inevitable, and practice has proved that waterborne container coatings are feasible. Waterborne container coatings have the advantages of environmental protection and safety, which will inevitably have a transformative impact on the application of container coatings in the future. In this paper, the film thickness specifications of container coatings of different systems and the comprehensive performance of solvent-based coating systems and waterborne container coating systems were compared. It is clarified that solvent-based coatings have higher corrosion resistance and salt spray resistance, and higher wear resistance and hardness than waterborne container coatings. Compared with solvent-based container coatings, waterborne container coatings are safer and more environmentally friendly, but their transportation, storage requirements and construction environment requirements are higher. The three-coat system and the two-coat system are the two mainstream supporting systems for existing waterborne container coatings. The basic composition of the two systems and the functions of each coating are analyzed. It is concluded that the waterborne epoxy coating used in the three-coat system waterborne container coating is obviously superior in adhesion and wear resistance than the two-coat system coating with waterborne acrylic as the inner and outer coatings, but the flexibility is relatively low. The waterborne vinylidene chloride resin in the two-coat system has strong barrier properties to water and oxygen, and has excellent anti-corrosion effect. The original three-coating is changed to two-coating, which improves the coating efficiency and saves the cost. It is pointed out that the technical bottlenecks of domestic waterborne container coatings mainly include high cost, harsh construction environment requirements, low wear resistance and hardness, and low salt spray resistance. The main research directions and latest research results in waterborne container coatings in recent years are listed. It is pointed out that the domestic container waterborne anti-corrosion primer has been widely used, but the waterborne epoxy-based curing agents are mainly imported brands, mainly because there is a certain gap between the domestic products and imported brands on certain aspects of salt spray resistance and stability. For domestic products, the salt spray resistance of waterborne epoxy resin dispersions varies from 200 to 600 hours. Finally, based on the current level of application development of domestic waterborne container coatings, it is proposed that in the preparation process of waterborne container coatings, more in-depth research and exploration in the synthesis and modification of coating resins or binders can be made to improve the comprehensive mechanical properties of the coatings. As the so-called three-part paint, seven-part spray, and spray paint process have been an important part of the water paint research and development process, advanced coating technology and equipment are indispensable in the process of continuous improvement and upgrading of waterborne container coatings, so as to realize the sustainable development of the waterborne container coating industry. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.