Common troubles and solutions of the hottest hose

2022-10-14
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Common faults and solutions of hose ink printing

1, poor whiteness

phenomenon: the ink surface is gray or yellowish after printing

cause: the whiteness of titanium dioxide used in the ink is not good, and the color of the connecting material is too dark, which affects the color; Not resistant to baking temperature, yellowing, insufficient amount of brightener and color finishing agent. Dirty color is introduced in the manufacturing process

solution: add titanium dioxide with pure white surface to the ink. It is best to use rutile titanium dioxide with no yellowing, good stability and good hiding power; Use resin oil with very light color, or use such resin oil to adjust inkability; Strictly control the baking temperature and time, and avoid excessive high temperature and long baking; Adding a small amount of cold color adjusting agent (phthalocyanine blue, ultramarine) or warm color agent (Fuchsia, green lotus, magenta 6b) can make the coating appear whiter; Strictly clean the printing machine to prevent color mixing or mixing with other colors. Don't put too much pressure on it, otherwise it will cause friction to turn gray and black

2. Chalking

phenomenon: the ink film after rolling coating will remove the toner with a gentle wipe, which is dim

reason: because the resin can not wrap the resin of pigment well; The amount of pigment is large, and the amount of resin is large. The resin can not wrap the pigment well to form a bright ink film

solution: increase the amount of resin and redeploy the ink; When it has been rolled and found as soon as possible, it can be rolled with a gloss to make up for it

3. Orange peel

phenomenon: lines like orange peel are formed on the coating surface

reason: because the solvent distillation range is too wide, there are many parts that evaporate rapidly, and the ink has not been leveled after roll coating. It is also for this reason that the leveling is hindered, thus forming the phenomenon of uneven surface. Because the resin used in the ink is too little, the cohesion is large, and the leveling property is not good

solution: Supplement leveling agents with high distillation range and improved leveling performance, such as octanol; Increase castor oil alcohol resin with good fluidity and improve the smoothness of ink

4. Sagging

phenomenon: after roller coating, place the print on the rack, or after drying, you can see that the ink flows together, and there is a shape concentrated in a certain place, which is not smooth and has poor brightness

reason: the ink is too thin and the leveling property is not good; The ink is too thick and the leveling property is not good, and the proportion is too large

solution: adjust the viscosity of the ink to spread it around in the flow process after rolling. Improve the cohesion of ink, so that it does not shrink into line due to leveling. Adjust the viscosity to an appropriate level, not too thick or too thin

5. Bottom exposure

phenomenon: after the roll coating, the ink layer on the metal is not thick, and the stretching trace of the aluminum tube or aluminum tube can be seen, or an empty line exposing the color of the metal tube is left after the roll coating roller leaves

the reason is to provide the greatest strength and durability for buildings, bridges, etc.: the viscosity of the ink is too small, the covering power is small, and the pressure is high, that is, the distance between the roller and the hose is too small, and the adhesion of the ink to the metal is too small

solution: adjust the ink viscosity to 85~95 seconds/25 ℃, not lower than 60 seconds/25 ℃, properly adjust the rolling pressure and increase the ink supply. Add epoxy or alkyd resin with good adhesion to the pipe

6. Folding and falling off

phenomenon: after the roller coating ink layer is dry, when folding and squeezing the contents at the bottom seal and in use, the ink layer cracks or takes off in powder form, exposing the metal pipe

reason: after drying, the ink layer becomes a brittle and hard coating. This is mainly because too much desiccant is added; The resin used is too brittle; The content of white material is too high. The ink is too thick and the ink layer is too thick. If the baking temperature is too high or the baking time is too long, an inflexible film will be formed

solution: when adding dry oil, try to reduce it as much as possible, so that the ink layer will form a flexible film after baking, and it needs some tests to obtain suitable local conditions; In view of the brittleness of the resin in the ink, the plasticizer dibutyl phthalate should be added, or alkyd, amino and other flexible resins should be added; Reduce the content of white pigment, subject to not affecting the hiding power and whiteness. The baking temperature should not be too high, 80-90 ℃ is appropriate, and the time should not be too long, 25-301 quarter minutes is enough

7. Pinhole

phenomenon: there are very small transparent holes in the film after rolling coating, such as pinholes

reason: due to the high surface tension of the ink, the metal tube is not well wetted, or the oil on the metal tube is too repellent to the ink; Due to the improper solvent ratio, especially the solvent that evaporates quickly, it rushes out violently and forms a vortex; A large number of bubbles are mixed in the ink, and if no bubbles are broken during baking; There are small particles in the ink binder that are not completely dissolved and have the same charge as the pigment, which repel each other and dry. All of these factors will cause small holes through the bottom

solution: first, use the scrubbing method to make the metal pipe clean; Add the solvent with proper proportion of fast drying and slow drying to make the evaporation speed moderate; Adding fetscher as an example: "a preform with unsuitable layering reduces the solvent of surface tension or slightly reduces the viscosity, so that the ink and metal are fully soaked; the ink is uniform, and the distance on the ink transfer roller is reduced, so that the bubbles in the ink are broken, and then printed after being evenly beaten.

information source: Chinese ink technology

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