The process of coating wrinkle oil on printed electrical tinplate sheets is as follows:
Coating wrinkle oil --- heat preservation baking wrinkle --- high temperature drying molding
1) Coating wrinkle oil is a four-roller coater, which uses a roller coating method to apply a layer of wrinkle oil with a uniform thickness on printed electrical tinplate sheets.
2) The operating viscosity of wrinkle oil is 25 ~ 30s, the amount used is about 15g / m², and the dry film thickness is about 10pm. The characteristics of the wrinkle oil directly determine the quality of the product, and the thickness of the coating cannot be ignored, too thick or too thin can not get the desired effect.
The film layer is too thick, with only large cracks and no wrinkles; the film layer is too thin, the pattern is unclear or the surface is smooth. In general, the color of printing inks has little effect on wrinkling of wrinkle oil. However, the wrinkling effect of some darker and darker colors is not good, and the best effect is to apply wrinkle oil on gold or silver (natural color of tinplate).
3) Low temperature baking and wrinkling on printed tinplate plate is the most critical process. The quality of the product is mainly determined by the control of baking temperature and time. Baking requires a special oven, such as a tunnel oven, to ensure uniform temperature distribution in the oven. Generally, liquefied petroleum gas or kerosene is burned, hot air is blown in, and drying is performed by convective heat transfer of air. The system now uses more advanced automatic ignition and constant temperature control technology.
4) In addition to the oven structure, which baking process is used, it is also related to the electrical tinplate sheets printing speed of the offset press. At present, most of the printing tinplate coil tin plate use low- and medium-speed offset printing machines with a rotation speed of 30 to 70 rpm. The offset printing press has a high rotation speed, a short drying time, and a higher drying temperature; and vice versa. Because the drying time and temperature have a compensation relationship within a certain range. If the baking temperature is too high, it will not wrinkle at all, and the effect is the same as that of varnish coating. If the baking temperature is too low, it will easily scratch the film layer, although it is wrinkled.
After low-temperature baking and wrinkling, the product has been basically formed, but it only needs to be touch-dried, and it needs to be dried at 140 ~ 145 ° C at high temperature for 10 ~ 15min, so that it can be completely dried to have excellent physical and chemical properties for stamping forming.
