Woven bag ink printing failure and troubleshooting

First, adhesion is not strong

Failure reasons: 1. Substrate surface and film or woven bag surface is too smooth (untreated or poorly processed). 2. Ink complexes (ie additives) were selected improperly or in insufficient quantities. 3. The dissolved hydrogen bond strength of the ink system is too different from the hydrogen bond strength of the woven bag substrate. Remedy: 1. The woven bag substrate surface reaches about 38 Dyne. 2. Add 5% of chlorinated paraffin before drawing the filaments. 3 ink selection should be very careful (the same nature). 4. The use of ink should be appropriate, as long as the viscosity is small and the ink system resin content is high. 5. Increase printing pressure.

Second, printing adhesion

Causes of failure: 1. Sticky bags or adhesions after rewinding during printing. 2. Because the printing speed is too fast, rewind too tight. 3. The drying device is not in the right angle or fails. 4. The ink is too dry. 5. Storage stacking pressure is too large. 6. The temperature is too high and the cooling is not complete or the ink is not heat resistant. 7. Ink dilute penetration back through India. Remedy: 1. Adjust the print speed and check the drying device angle. 2. Improve the dryness of the ink (or increase the ethanol 90 + ethyl ester 10% mixed diluent). 3. When printing, there are few stacks or storage stack load is light. 4. Reduce the temperature of the workshop or warehouse (open the door to allow air convection, etc.) and replace the heat-resistant woven bag ink. 5. Add the original ink to increase its viscosity or add a small molecular weight solvent and then dilute the solvent quickly (advantageous thinner recommended by the ink factory).

Third, residual odor

Cause of failure: 1. There is a smell of raw materials in the ink. 2. The ink deteriorates. Remedy: 1. Try not to use odorless raw materials. 2. Add spices (masking agents) and prevent impurities from penetrating the ink system. 3. Ink production Pay attention to the solubility of the mixed solvent on the resin or the ink is stored in a cool and cool warehouse.

Fourth, poor film formation

Cause of failure: 1. The printing speed does not match the drying device or dryness of the ink. 2. Misuse of thinner. 3. The ink itself is not dry (such as too slow or too fast). Remedy: 1. Increase the air blow or increase (extension) the post-printing conveyor belt. 2. Adjust the printing speed (pay attention to the ink film thickness after printing). 3. Re-exchange dry fast (filming) ink. 4. Replace ink. 5. Re-dilute or add a solvent with a fast evaporation rate.

Fifth, blocking version

Failure reasons: 1. The ink is mainly dried on the printing plate to make ink transfer poor. 2. Mix in plastic or paper scraps. 3. Ink crusts. Remedy: 1. Adjust the blowing angle (not directly on the plate). 2. In addition to changing the substrate, the upper side of the printing press should be separated from the fountain ink by the base paper, plastic or film. 3. Replace the new ink or add 10% antioxidant to its ink fountain.

VI. Printout or migration

Failure reasons: 1. Ink is too thin (that is, the viscosity is too small). 2. Thin paper or plastic substrates. 3. Ink is too large. 4. Pressing too much pressure. 5. Filming is too slow. Remedy: 1. Incorporate original ink or add thickener. 2. Replace compact substrates. 3. Replace with a dry ink or add a fast solvent. 4. Adjust (reduce) ink supply. 5. The pressure should be light.

Seven, bleeding

Causes of failure: 1. The printed graphics are infiltrated with color at the edges (generally caused by dyes used in the ink). 2. The use of pigments is not properly matched or the ink has deteriorated. 3. Excessive thinner material is used, especially poor compatibility with ink and ink. Remedy: 1. Add gold oil or add coupling agent to the ink. 2. Select a solvent (such as alcohol solvent) pigment or replace it with a new one. 3. Minimize the use of thinner materials, especially solvents that are compatible with the ink.

Eight, ink film no light

Failure reasons: 1. Luster is poor. 2. Inhalation of water is distributed during the film formation. 3. The ink is rough. 4. The ink is drying too fast. 5. The ink system contains little or no matting agent. In high temperature and high humidity in summer, especially in the coastal areas, the ink absorbs the moisture in the air during the printing process and damages the oiliness, thereby reducing the gloss. Remedy: 1. Add 3% to 5% cyclohexanone or 2% to 4% ethers in the ink to resist intrusion of water molecules. 2. Re-grind or filter the ink. 3. Use slow-drying solvents to supplement the ink system. 4. Add 5% to 15% of the resin solution in the ink fountain. 5. Do not add or add less matting agent (such as wax, white carbon, etc.). 6. Replace the glossy ink or use less solvent to dilute.

Reprinted from: 21st Century Fine Chemicals Network