Post-press processing technology: polishing process for color printing paper products

The polishing process is a process that uses high temperature and high pressure to make the varnish oil film that has been formed into a mirror like a mirror, thereby obtaining a brighter and smoother effect. In the past few years, the polishing process is mainly used in the solvent-based polishing process. Water-based polishing cannot be polished. With the advancement of waterborne varnish production technology, polishable waterborne varnish has been put on the market.

1. The basic principle of polishing process

The polishing process is also called calendering process, which makes the temperature of the steel belt of the polisher reach about 90-105 ° C through high temperature, so that the varnish oil film is quickly softened, and a 200-250kg / cm 2 is applied to the surface of the printed product while softening The pressure makes the surface of the printed product smooth like a mirror. Finally, the printed product is peeled off from the steel belt, and the entire polishing process is completed.

2. How to ensure the stability of the polishing quality

Pay attention to the following points when polishing:

2.1. The polishing temperature is moderate. If the temperature is too high, it is difficult to remove the plate and damage the oil film.

2.2. The polishing pressure should be appropriate, and the pressure should be adjusted according to the thickness of the cardboard and the polishing effect. The general pressure should be kept around 200-250kg / cm 2 .

2.3. To obtain a good mirror effect, the oil layer should not be too thin when glazing, and the best polishing effect is about half an hour after glazing.

2.4. To ensure the stability of the polishing quality, there are two other points that must be achieved: one is to avoid a pause in the middle, and the other is to keep the polishing speed stable.

3. Cause analysis and improvement countermeasures for common problems of solvent-based and water-based glazing