升温曲线对彩涂板性能的影响

天物彩板专注彩涂卷行业17年——升温曲线对彩涂板性能的影响_hv248版型彩钢板请拨打网站上方电话咨询

彩涂板在烘烤过程中，板温逐渐升高，使涂料中的溶剂挥发，逐渐交联固化。由于固化炉各段的温度可以单独控制，带钢最终可以通过不同的温升曲线达到pmt值。然而，炉内第一段和第二段带钢的温度通常控制在略低的水平，以便在漆膜固化之前，漆膜中的溶剂能够完全挥发。如果温度上升过快，涂层中的溶剂溢出过快，或漆膜中的溶剂挥发太晚，则漆膜已固化，这将导致表面出现气泡等缺陷。

在熔炉的第三段和第四段，带钢的温度略高于涂层的固化温度。当带钢进入第三阶段时，溶剂基本蒸发，漆膜开始凝固。此时，主要是化学干燥过程，而涂料是聚合的。因此，应加强热风循环，加快反应速度；但如果风速过高，会破坏漆膜形成过程中各阶段的平衡，容易产生起皱、光泽度降低等缺陷。在熔炉的第五段，带钢温度略微降低或保持不变，如图2所示。如果所有温度相同，即带钢温度呈线性上升趋势。虽然带钢最终可以达到固化温度，但由于在该温度下的时间短和交联密度低，涂层的耐磨性和耐溶剂性将降低。烘烤固化温度对彩涂板的其他性能也有影响。涂覆样品后，控制不同的PM t温度，以改善固化后的性能。
可以看出，随着烘烤温度的升高，涂层的光泽度降低，硬度增加，T形弯曲度降低。这是因为随着固化温度的升高，涂层的交联固化程度增加，涂层的致密性增加，涂层的耐擦洗性、硬度和耐划伤性提高，而T型弯曲性能降低。因此，生产中应控制带钢PMT的波动，以保证涂层性能的稳定性。

In the baking process of color coated plate, the plate temperature increases gradually, so that the solvent in the coating can volatilize and gradually crosslink and cure completely. Since the temperature of each section of the curing furnace can be controlled separately, the strip steel can finally reach the PM t value through different temperature rise curves. However, the temperature of the first and second sections of strip steel of the furnace is usually controlled to be slightly lower, so that the solvent in the paint film can be fully volatilized before the paint film is cured. If the temperature rises too fast, the solvent in the coating overflows too fast, or the solvent in the paint film is too late to volatilize, the paint film has been cured, 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 steel enters the third stage, the solvent has basically evaporated, and the paint film begins to solidify. At this time, it is mainly the chemical drying process, and the coating is polymerized. Therefore, the hot air circulation should be strengthened to speed up the reaction; However, if the wind speed is too high, it will destroy the balance of each stage in the process of paint film formation, and it is prone to wrinkle, gloss reduction and other defects. In the fifth section of the furnace, the strip steel temperature slightly decreases or remains unchanged, as shown in Figure 2. If all temperatures are the same, that is, the temperature of the strip steel shows a linear upward trend. Although the strip steel can finally reach the curing temperature, the wear resistance and solvent resistance of the coating will be reduced due to the short time at this temperature and low crosslinking density. Baking curing temperature also has an effect on other properties of color coated board. After coating a sample, control different PM t temperatures to improve the properties after curing.

It can be seen that with the increase of baking temperature, the gloss of the coating decreases, the hardness increases and the T-bend decreases. This is because with the increase of curing temperature, the crosslinking curing degree of the coating increases and the compactness of the coating increases, so that the M EK wiping resistance, hardness and scratch resistance of the coating improve, while the T-bend performance decreases. Therefore, the fluctuation of strip PMT should be controlled in production to ensure the stability of coating performance.