Treatment of common problems in the calendering pr

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Treatment of common problems in the glazing and calendering process

first, there are stripes on the film surface or reduce the existence of unstable friction wrinkles

"the viscosity quotient of the glazing oil is too late to level, and it is easy to have stripes. You can choose the glazing oil with good leveling and wettability according to the different suitability of the printed matter; Or add an appropriate amount of diluent to reduce the viscosity of glazing oil mXz ⑴ friction coefficient meter. If the coating amount is too large, the coating amount can be reduced by adjustment; Sometimes it is the poor wettability of the polish on the ink layer on the surface of the print, which affects the smoothness of the drying film, or the poor leveling of the Polish, and the process conditions do not match the suitability of the polish. Other types of polish can be selected or the process conditions can be changed to match the performance of the polish

; It may also make the coating film too thick, the solvent inside the coating is not completely volatilized, and the residue is high, which can reduce the coating amount and reduce the thickness of the film layer; Or the working temperature is low in glazing coating or calendering, and the drying time is short, which makes the coating dry poorly. It can improve the working temperature in glazing coating production and calendering, reduce the machine speed, and make the coating dry completely

II. Poor gloss of film-forming film

. If it is the quality problem of glazing oil, it should be considered to use a better quality glazing oil according to the process and economic requirements; If the coating is too thin, the coating amount is insufficient or the glazing oil concentration is small, and it is difficult to fill the surface of the printed matter with high roughness and strong absorption, the coating amount should be increased to increase the coating concentration, or a layer of glazing primer should be applied before processing, and then glazing and coating should be carried out. It may also be that the temperature of glazing and coating drying and calendering is low, and the calendering pressure is small, then the process parameters should be adjusted during operation to increase the temperature and pressure; It is also estimated that the reason is the equipment itself. If the gloss smoothness decreases due to the wear of the calendered steel strip, it is necessary to repair and improve the surface condition of the calendered steel strip

III. After calendering, the blank part of the print is light colored, and the light colored part changes color

. The glazing solvent dissolves the ink layer to a certain extent. The national standard gb/t 9341 ⑵ 000 describes the experimental steps in detail, which requires changing the type of glazing oil or changing the solvent composition; If the ink dries poorly and the solubility resistance of the ink layer is not good, it is necessary to improve the ink drying condition, and then polish and coat after the ink dries, so as to reduce the amount of solvent that dissolves the ink in the glazing oil; If the layer is not completely dried and the solvent residue in the film is high, it is necessary to increase the drying temperature or reduce the machine speed during glazing and coating, extend the drying time and reduce the solvent residue in the coating

IV. uneven coating, bubbles, pockmarks, etc.

v. blistering on the film surface

in the calendering process, the pressure is too high, and the temperature of the calendering steel strip is too high, which makes the glazing film locally soften, which requires appropriate reduction of the calendering pressure and temperature; It may also be that the glazing oil does not match the calendering process conditions. Hero has also made history. After the glazing layer on the surface of the print is cooled, the stripping force of the same light band is poor. It is necessary to change the process conditions to match it with the glazing oil, reduce the calender speed, and improve the stripping force between the glazing layer and the same light band

VI. in calendering, the adhesion between printed matter and glazing tape is poor. The coating is too thin, so the coating amount should be increased; The viscosity of glazing oil is too low, so it is necessary to improve the viscosity of glazing oil; Then, the pressure of calendering is too small, and the calendering temperature is insufficient. It is necessary to increase the calendering temperature and pressure

VII. After calendering, the surface of the printed matter is easy to crack

. The temperature is high, which makes the printed matter dehydrate too much during the calendering process, and the water content is reduced, so the paper fiber becomes brittle. The working temperature of calendering should be reduced, and effective measures should be taken to maintain a certain water content in the printed matter; Excessive pressure in calendering reduces the extensibility and plasticity of the printed matter, and toughness can reduce the pressure in calendering; If the post-processing suitability of the glazing oil is poor, the glazing oil with better processing suitability should be re selected; If the post-processing process conditions are not suitable, the post-processing process conditions can be adjusted to match the suitability of the printed matter after calendering

VIII. The brightness of the film surface on both sides is inconsistent after calendering

. In calendering, the pressure on both sides of the calendering belt is not equal, and the wear on both sides of the calendering belt is not uniform. The pressure on both sides of the calendering Belt should be adjusted to make it equal, and the parallelism of the hot pressing roller and the transmission roller should be adjusted to make both sides of the calendering belt tensioned and worn evenly; It may also be that the thickness of both sides of the glazing oil is uneven, so it is necessary to adjust the glazing coating mechanism, check the parallelism and gap between the metering roller and the coating roller, and make the coating thickness on both sides as consistent as possible

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