At present, the main problems of functional coatings are coating color difference, missing coating, coating flatness and stretch of base film, and coating drying consistency. The key core technology to solve the above problems is the oven drying technology.
To solve these problems, in addition to the quality of the coating itself, the uniformity and flatness of the coating, the uniformity of drying in the oven and the consistency of the evaporation rate of water and solvents appear to be very critical. First, the inner film of the oven must be operated under low tension and low temperature to ensure the stability and invariance of the operation of the base film. Secondly, it is necessary to ensure the consistency of the drying effect and to require the coating to have a low and uniform moisture content.
First, the breakthrough in the application of oven technology
Due to the relatively mature development of transfer and anodized aluminum coating technology in China, Shantou Ouge Company has conducted in-depth research on the existing problems of film coating, and has used film mastering technology to apply film coating equipment. The development, especially in the oven drying technology, has an invention patent and a unique technology, which has a special effect on the low temperature drying and uniform consistency of the base film.
The specific oven structure technology is detailed as follows:
1. High precision wind nozzle design and manufacturing technology. The temperature deviation at the arbitrary point of the outlet of the wind nozzle is only ± 1 ° C, and the deviation of the vertical accumulated value of the wind speed and temperature is controlled within ± 1% to ensure the uniform heat exchange amount.
2.The oven adopts a point-to-point, equidistant upper exhaust gas structure. The exhaust gas exhaust ports are evenly arranged between the two air nozzles, which achieves a uniform air flow field on the substrate surface, thereby ensuring solvent saturation at any point in the lateral direction of the substrate coating surface. Of agreement.
3. Due to the consistency of the heat exchange amount of the oven and the consistency of the solvent saturation at any point in the lateral direction of the substrate surface, the consistency of the volatilization rate at any point on the coating surface is guaranteed (this technology is better than similar equipment in Japan and South Korea), and The drying effect of the product is consistent. Compared with the traditional oven with exhaust gas on both sides, in addition to the advantages of temperature, air heat exchange value, and humidity field with 99% consistency, the new oven technology has no internal stress.
4.The surface of the substrate between all the nozzles can be dried under the pressure of ± 10Pa in the micro pressure field, and the drying efficiency is high, thereby achieving low-temperature drying operation (compared with similar domestic equipment); and also the base film No drift and low tension operation in the oven.
5. Comparative analysis of ceramic diaphragm application cases: Under the same production process conditions: water-based ceramic coatings with a solid content of 40%, a viscosity of 80Cps, and a dry coating volume of 4um. Compared with domestic equivalent equipment, the comparison table of main parameters is as follows:
Advantages of precision coating equipment
In addition to the improved oven, which can ensure the consistency of low-temperature coating drying, Ouge coating equipment technology also includes the advantages of materials that can run at low tension and increase production efficiency by more than 20%.
1.Low tension operation of material
The single-side coating equipment is a 4-segment high-sensitivity low-tension control system. The tension mechanism is controlled by low-friction cylinder + precision pressure regulating mechanism + servo proportional valve + PLC control program and calculation, and cooperates with high-precision tension sensing roller device. Segmented tension closed-loop control and precise assembly of the guide roller set, so that the tension is not affected by roll change and connection. A vacuum suction roll (bed) is set in front of the oven, so that the tension of the diaphragm in the coating section is stable and controllable, which is conducive to the high-speed operation of thinner substrates. Secondly, the oven is uniformly dried and the wind speed is uniform. So that the base film of the coating in the oven will not drift laterally, and there is no need to rectify the exit of the oven, so that there is no defect of the elastic side of the film.
2. Low temperature drying consistency of coating
The temperature error at any point of the air nozzle of each oven is ± 1 ℃, and the error of the longitudinal wind speed and the temperature accumulated value is within 1%. Excellent, under the condition of the same mechanical speed, the required temperature is about 20% lower, the coating has higher physical properties of resistance to bending, and the drying is uniform, which makes the coating have stronger adhesion, more uniform drying and no surface aging Such defects, the performance of the coating base film is consistent with the original base film.
3. Under the same conditions, the efficiency is improved by more than 20%
Efficiency is mainly reflected in three aspects: first, the production speed can be faster, the key is the stability of the tension and the guarantee of the drying effect; the second is the efficiency of the rewinding and unwinding, the unwinding tension without fluctuation and loss, and the winding without bottom wrinkles . The third is simple and effective operation. The perfect control system can realize full-automatic operation, and it can still run at a constant speed when rewinding, rewinding, and rewinding (the drying time of all coating films in the oven is the same). No need to lower / up speed, the consistency of the product is obtained. Protection.
4, the whole process of digital monitoring production (functional indicators are better than Japanese and Korean equipment)
The whole process speed, tension, temperature, and oven air intake / exhaust volume are displayed / operated / real-time monitored on the touch screen. Oven micro-pressure monitoring device, coating water PPM online monitoring, etc. Throughout the digital production process, finished products that can be controlled, traced, and relied upon, and which have superior quality, are fully guaranteed.
Ouge single-sided coating machine