彩涂板对炉内环境的影响

彩涂板生产前，应确保固化炉内无灰尘和其他异物，以避免生产过程中因落在涂板表面而产生缺陷。漆膜吸收水分时，容易出现膨胀、粉化等异常现象。另外，彩涂板当湿度较高时，防止漆膜中溶剂的挥发，影响漆膜的固化质量，因此要求固化炉内的湿度较低。

使用环氧树脂（含脂肪酸酯）、醇酸树脂、三聚氰胺树脂时，炉内的酸性气体（过氧化氢、二氧化硫、二氧化碳）会在涂层表面相互作用，产生皱纹和深裂。固化工艺是彩色涂料生产中的关键工序。钢板的温度、时间和温升曲线的控制，直接影响到彩涂板的T形弯曲、铅笔硬度、光泽度、耐磨性、耐溶剂性等性能，对不同颜色涂料的色差有不同的影响。在实际生产过程中，这些因素会对产品产生综合影响，增加分析和调整的难度。另外，彩涂板由于各生产线采用的工艺布局和涂装体系不同，在生产中要逐步探索规律，建立一定的对应关系，以便更好地控制产品质量。在烘烤过程中，钢板的温度逐渐升高，涂层中的溶剂挥发，逐渐交联固化。
彩涂板由于每段硫化炉的温度可以单独控制，通过不同的加热曲线，带钢最终可以达到PMT值。但是，通常控制第一段和第二段炉的温度略低，以便在漆膜固化之前，漆膜中的溶剂能够充分挥发。如果温度升高过快，涂料中溶剂溢出过快，或者漆膜中的溶剂没有及时挥发，漆膜已经凝固，会造成表面气泡等缺陷。在第三段和第四段炉内，带钢的温度略高于涂层的固化温度。当铜带进入第三部分时，溶剂已经蒸发，薄膜开始凝固。此时，涂层的主要缺陷，如风速过大，会加速化学皱纹的形成。色差是彩涂板的一个特殊性能指标。在CIE标准色系中，涂料产品与标准板的色差以$e表示。固化温度对色差的影响不同。对于大多数涂层，如白灰色和海蓝，色差在一定的温度范围内（通常为224~241e）基本稳定。对于敏感的猩红，固化温度对色差有很大的影响。这是因为通常在猩红颜料中加入有机颜料，这种颜料稳定性差，对温度敏感。因此，在生产大红漆时，必须严格控制固化温度

Before the production of color coated plate, it should be ensured that there is no dust and other foreign matters in the curing furnace, so as to avoid defects caused by falling on the surface of the coated plate during production. When the film absorbs moisture, it is easy to appear swelling, chalking and other abnormal phenomena. In addition, when the humidity is high, the volatilization of solvent in the film is prevented, which will affect the curing quality of the paint film, so the humidity in the curing furnace is required to be low. When epoxy resin (containing fatty ester), alkyd resin and melamine resin are used, the acid gas (hydrogen peroxide, sulfur dioxide, carbon dioxide) in the furnace will react with each other on the surface of the coating, resulting in wrinkle and deep crack. Curing process is a key process in color coating production. The control of temperature, time and temperature rise curve of steel plate directly affects the T-bend, pencil hardness, gloss, wear resistance, solvent resistance and other properties of color coated plate, and has different effects on color difference of different color coatings. In the actual production process, these factors will have a comprehensive effect on the product, increasing the difficulty of analysis and adjustment. In addition, due to the difference of process layout and coating system used in each production line, it is necessary to gradually explore the law in production and establish a certain corresponding relationship, so as to better control the quality of products. In the baking process, the temperature of the steel plate increases gradually, which causes the solvent in the coating to volatilize and gradually crosslink and solidify completely.

Because the temperature of each section of the curing furnace can be controlled separately, the strip steel can finally reach the PMT value through different heating curves. However, the temperature of the first and second sections of the furnace is usually controlled to be slightly lower, so that the solvent in the paint film can be fully volatilized before the film is cured. If the temperature is raised too fast, the solvent in the coating overflows too quickly, or the solvent in the paint film does not volatilize in time, the paint film has solidified, which will cause defects such as bubbles on the surface. In the third and fourth sections of the furnace, the temperature of the strip steel is slightly higher than the curing temperature of the coating. When the strip enters the third section, the solvent has evaporated and the film begins to solidify. At this time, the main defects of the coating, such as high wind speed, will accelerate the formation of chemical wrinkle. Color difference is a special performance index of color coated board. The color difference between coating product and standard board is expressed by $e in CIE standard color system. The influence of curing temperature on color difference is different. For most coatings such as white gray and sea blue, the color difference is basically stable within a certain temperature range (usually 224 ~ 241 E). For the sensitive scarlet, the curing temperature has a great influence on the color difference. This is because organic pigment is usually added to the scarlet paint, which has poor stability and is sensitive to temperature. Therefore, it is necessary to strictly control the curing temperature in the production of scarlet paint.