The effect of using benzene-free and ketone-free ink is always bad, so try these tricks!

Before the official printing, the soft package enterprise should first determine the printing speed according to the performance of the printing equipment and the printing materials. The faster the speed, the higher the ink transfer rate, and the better the printing effect; the slower the speed, the lower the ink transfer rate, resulting in poor leveling and uneven hue. In severe cases, it may also cause dry plates, blocked plates, and no coloring.

2. Solvent ratio and ink viscosity

The most important indicator of solvent ratio is dissolving power, followed by volatilization rate, and at the same time it is one of the important factors that directly affect the residual amount of product solvent. The volatilization speed of the solvent is mainly affected by the temperature, vapor pressure, variable area and volume, and the speed of air flow on the surface. The formula of fast-drying, medium-drying and slow-drying solvents should be adjusted reasonably according to the printing shallow screen transfer effect and printing speed. Adjust the working viscosity of the normal production of ink printing to ensure that the ink viscosity and volatilization speed adapt to the production conditions to achieve the best printing effect.

It is recommended to equip the workshop with a slow-drying solvent, and adjust the viscosity of the ink to the viscosity value during normal production before production. Then, during normal production, when the quality meets the product quality requirements, measure the viscosity again, which can be used as the standard viscosity for control. The time is measured every 20 minutes. Controlling the viscosity can effectively reduce the quality problems such as the difference between the residual amount and the hue.

3. Angle, pressure, distance between ink scraping point and imprinting point

The angle and pressure of the doctor blade will affect the doctor blade effect and the ink transfer rate in the gravure mesh. The angle of the doctor blade is generally 45-65 °. The distance between the ink scraping point and the imprinting point should be moderate.

4. Imprint force

The embossing force has a great influence on the ink transfer. Improving the embossing force can increase the interaction force between the substrate and the printing plate, thereby improving the ink transfer rate. Excessive pressure will cause "double eyelids", ink spillage, etc. Generally, it is appropriate to control the embossing force within the range of 2kg-3KG. If it is a character layout, it is more appropriate to choose a pressure roller with a hardness of 70-72HS. For a large-area spot color, it is more appropriate to use a soft pressure roller of 65HS.

5. Oven temperature

The oven temperature is determined according to the substrate. In general, the oven temperature when printing BOPP, PE, CPP films is set to about 50-65 ° C; the oven temperature when printing PET, NY films is set to about 50 ° C. If the temperature of the oven is too high, it will accelerate the volatilization of benzene-free and ketone-free ink solvents, resulting in surface drying phenomenon. At this time, the amount of cold air should be increased.

6. Surface tension of substrate

Choose the original materials as much as possible, such as BOPP to achieve at least 37 dynes, which will help the wetting effect of benzene-free and ketone-free ink on the film, which is conducive to the transfer effect of shallow net graphics.

7. Production of gravure roller

The gravure plate-making supplier shall determine the depth and the number of screen lines of the gravure plate according to the speed of the printing equipment of the flexible packaging color printing enterprise, the suitability of the printing material, and the analysis of the manuscript, especially the fine gradation of the highlight area and the saturation of the light-tone area , In particular, it has a greater impact on the subtle gradation of highlight areas and the saturation of light-tone areas.

In addition, gravure plate-making companies should also fully consider the performance of inks used in flexible packaging color printing companies. Under the premise of ensuring printing quality, gravure meshes with low application speed should be carved slightly deeper to facilitate the full entry of ink Into the net hole, to further increase the demand for ink transfer in graphic parts.