Current situation and future thinking of waterborne container coatings

Because of its particularity, the shipping and container industry pays more attention to the anti-corrosion coating. The container is a special tool for international logistics and transportation, its use environment is complex and changeable, and its steel structure corrosion is inevitable. This puts forward requirements for the anti-corrosion performance of container coatings. On the premise of meeting the anti-corrosion standards, we advocate more green environmental protection, so this paper discusses more environmentally friendly waterborne coatings. The annual output of containers in the world is huge, and the annual demand for coatings on the outer walls of containers is of great value. Five years ago, the containers used in the world were basically solvent based coatings. In recent years, the use of water-based coatings in the container industry has become a consensus in the industry, and new water-based environmental protection coatings are being uniformly promoted all over the country In Guangdong, Maersk Dongguan Container Industry Co., Ltd., a factory specializing in the production of ordinary containers, the biggest difference here is that the working environment of the factory is more environmentally friendly and safe coating. The factory water-based paint replaces the traditional oil-based paint.

The coating industry issued a statement very early that the container industry should adopt a self-discipline way, and every enterprise consciously uses more environmentally friendly materials to replace the traditional oil paint, which is the so-called "joint commitment and joint action", and this sentence is not just a slogan, we see the change from the actual results At present, the enterprises with high VOC emission in China's container manufacturing enterprises, from the position of "who protects the environment, who loses money, who insists on closing the door", to who protects the environment, who benefits from it, the hardships are self-evident, but the actual results are also obvious to all. At present, the northern, Shanghai and Guangzhou regions where the container industry is relatively concentrated have gradually started to promote the use of waterborne coatings, which will be restricted in the national areas in the future At the same time, the new type of water-based environmental protection coating should be promoted In 2019, the key year for the development of environmental protection industry, people's awareness of environmental protection has been generally improved.

The policy of changing oil into water is not only limited to container coating, but also all walks of life. Since April 1, 2017, the coating production line of national standard dry container manufacturers has changed from solvent based coating system to water-based coating system The water-based coating uses water as the dispersing medium. Generally speaking, the water-based coating uses water to mix the paint. The volatilization of the water-based coating in the spraying and drying process is water, and its VOC emission is very small. The data shows that VOC emission of waterborne coatings can be reduced by 60% ~ 70% compared with solvent based coatings. Therefore, waterborne coatings are more and more popular. The external box body is equipped with solvent epoxy iron red primer, water-based epoxy intermediate paint and polyurethane finish paint. The internal solvent epoxy primer and water-based epoxy finish paint can reduce the cost of water-based coating and control the VOC emission. In fact, it is not only the container industry, but also the general trend of water-based coating industry. Water-based container coating is soluble The collocation of dosage form coating is the key point that everyone pays close attention to. The development trend of waterborne container coating is: environmental protection, the discharge of waterborne paint is cleaner than that of traditional paint in the process of coating construction, and it is mostly natural degradable substances and water, so the purpose of environmental protection is achieved.

However, it should be noted that some poor water-based paints will lead to more problems, which is mainly due to the cumbersome process and also related to the self-discipline of enterprises. In this regard, we need more guidance. The waterborne paint is not completely environmentally friendly. For people, no matter what kind of paint is harmful, but what can be determined is that the impact on the environment is very small compared with the traditional paint, especially the waterborne paint is constantly updated, each generation of products pay attention to the improvement of environmental protection performance. Due to the existence of zinc powder, the waterborne epoxy zinc rich coating can effectively carry out cathodic protection for the box body, delay the corrosion progress of the box body, and prevent the paint film from falling off due to collision, so the system has been unanimously recognized by the industry There are some limitations in the waterborne container coating, such as high cost, high construction environment requirements, such as temperature, humidity, ventilation, etc., which will affect the performance of the coating, and its own construction performance is relatively poor, which is difficult for workers to master. Due to the poor quality and difficult construction of this generation of products, it is very difficult to promote waterborne paint in China in the future.

As long as workers have been exposed to this kind of waterborne paint, they will habitually conflict. The more products are sold, the more difficult it is to promote waterborne paint. Temperature difference, one of the biggest shortcomings of water-based touch up paint is the strict requirements of temperature, which is a great challenge for construction. This leads to a series of problems, such as storage and transportation problems, as well as risk control. The film of water-based paint is thinner than that of oil-based paint, which means that it is easy to be scratched. The water-based paint is also easy to crack, and the water-based paint with good quality does not have such problems, so it can be considered that the gloss and fullness of the paint film are not as high as that of the paint abroad; the wear resistance is not as high as that of the paint, which is not suitable for the desktop and the desk, and suitable for the cabinet, door, etc. There are some water-based paints whose film hardness can not reach the level of oil-based paint, so it is necessary to brush several times more than oil-based paint, and the construction technical requirements are also higher than oil-based paint.