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　　In order to ensure that the waxy asphalt paint at the bottom of the box has good anti-corrosion performance, give full play to its excellent construction performance, and meet the quality requirements of the box car for the varnish at the bottom of the box, the close cooperation of the container manufacturer is required, and the close cooperation of the correct coating process and the appropriate construction technical conditions is required.

　　The structure of container bottom is very complex. The inner side of corner parts, the opposite side of lower truss and the inner side of threshold cannot be sprayed with spray gun; the width of bottom crossbeam is less than 20cm, so it is difficult to spray evenly. Therefore, the container factory must set the pre coating and pre spraying station of asphalt paint, and strengthen the pre spraying process to ensure the coating quality of asphalt paint at the bottom of container.

　　Waxy asphalt is a kind of thick paste paint. In order to obtain a dry film of 200 μ m in one painting, the high pressure airless painting method must be used. (1) Pump: at present, in the container industry, the king55:1 pressure plate high-pressure airless spray pump of American Graco company is used for the spraying of waxy asphalt paint, and the 18C pump produced by Changjiang Machinery Factory of China Shipbuilding Corporation is also used in some container plants, both of which have large flow, but the paint must be fully mixed before the painting of 18C pump. (2) Painting pressure: the painting pressure required for waxy asphalt is 18.0 ~ 20.0Mpa. The operator should adjust the best air inlet pressure according to the compression ratio of high-pressure airless painting pump, such as king55:1 pump. When spraying waxy asphalt paint, the air inlet pressure should be about 0.35Mpa. (3) Spray nozzle: correct selection of spray nozzle is the key to ensure the quality of paint film and production progress, and also the necessary means to control paint consumption and reduce the cost of box making. Under the above pressure, the technical conditions for spraying the special nozzle for waxy asphalt paint are: spraying width 20 ~ 25cm, flow 5000ML / min. Nozzle aperture: 0.94mm. The spray nozzle code of American Graco company is 163-437, and that of Changjiang Machinery Factory is 050p25. In production, rotary nozzles with the same technical conditions are used.

　　Only 3 years have passed since the wax based asphalt paint was developed in China. As a new product, it must be improved in the development. In my opinion, the work should be carried out from the following three aspects:

　　(1) As a paint factory, we should constantly summarize the experience and lessons of batch production, improve the formulation, and make the quality of waxy asphalt paint better.

　　(2) Domestic container trucks, such as COSCO and sino-trips, should strongly support the development of domestic waxy asphalt paint; container factories all over the country should also actively cooperate to make the construction performance of waxy asphalt more mature and perfect.

　　(3) Samples shall be sent to the United States for testing and approval by konstandt laboratory. The purpose is to make the wax containing asphalt produced in China comparable to tectyl121b, and to better serve the container industry at home and abroad.

　　转载于李敏风老师的<防腐涂料与涂装>Reprinted in Li Minfeng's <anticorrosive coating and coating >