How to solve the problem of printing adhesive labels

Self-adhesive label is also called self-adhesive label. The material is paper, film or other special materials as the fabric, the back is coated with adhesive, and the 1 composite material is coated with silicon protective paper as the backing paper. After printing, die cutting, etc., it becomes a finished label. Self-adhesive label Compared with traditional labels, it has the advantages of no glue brushing, no paste, no dipping in water, no pollution, saving labeling time, etc., and has a wide application range and is convenient and fast.

self-adhesive materials are usually printed and processed on label linkage machines. the most common printing form is embossing, and other printing methods are also used. The common faults in the printing stage are roughly the following:

Failure 1: The ink layer on the printed label surface does not dry, dries slowly or the ink layer is 1 wiped off

reason: too thick printing ink layer, too large amount of ink, inappropriate additives used in ink, ink denaturation or inappropriate type of ink used, etc. will all cause the printed label ink layer to not dry, dry slowly or 1 the ink layer; in addition, the machine runs too fast and dry.

Solution: 1. Use deep ink thin printing method to reduce the thickness of ink layer; 2. Use special ink with fast drying speed; 3. Use matching additives and add matching desiccant; 4. Take measures, extend the drying or curing time of the printed matter; 5. Increase the room temperature, appropriate amount of exhaust, and accelerate the drying speed of the ink.

2 of failure: film surface printing ink layer adhesion fastness is poor, easy to drop ink

if the surface of the film is not corona treated, or the surface tension of the film is lower than that of the ink, the ink is not easy to adhere; This kind of failure can also occur when the unused ink does not match the characteristics of the film material or the special ink is not used; and the use of expired or failure of ink also inevitably such failure. In addition, the power of the drying device (U V or infrared hot air drying) is low, resulting in that the ink cannot be completely dried or the printing ink layer is too thick, the ink amount is too large, and the ink viscosity is too large, resulting in embrittlement of the ink after long-term drying, which will also lead to poor adhesion fastness of the printed ink layer on the film surface and easy ink drop.

solution: increase the surface tension of the printing material, requiring the surface tension value to reach 38 dynes/cm or more; 2. The rotary labeling machine should be equipped with corona device to increase the surface tension of the film; 3. Transparent solvent-based ink can be used to make a reservation first to improve the surface tension of the printing material; 4. Select special inks and matching additives that match the printing material; 5. Increase the drying or curing power, or reduce the machine running speed and increase the drying time; 6. The printing ink layer should be as thin as possible, and the amount of ink should be as small as possible. If necessary, monochrome can be overprinted many times; 7. U V glazing after recommend printing to protect the printing ink layer and increase the adhesion fastness of the ink layer.

failure 3: uncoiling printing is not possible after the end face of the roll of fragile paper seeps glue

reason: when cutting and rewinding small rolls, the rewinding tension is too high, resulting in too tight rewinding, which will cause this failure; Too high temperature in storage or printing workshop will also cause this failure. Extrusion or long storage time is also one of the reasons for this failure.

Solution: 1. In addition to improving the corresponding storage and processing conditions for the above reasons, alcohol can also be used to wipe and infiltrate the adhesive end surface to dilute the adhesive and reduce its viscosity, so as to facilitate uncoiling; 2. Gently uncoiling, powder on both ends and rewind slowly; 3. The improved roll adhesive material should be printed and die-cut slowly on the label machine of intermittent paper feeding.

4 of failure: partial ink drop on the surface of the printed film-inconsistent ink adhesion fastness

reason: first, when multi-color overlapping printing, the bottom ink is covered by the surface ink before it is completely dried; Second, because the ink layer is too thick, the exposed ink of the same color has been completely dried, while the ink pressed underneath is still not dried, the UV curing function of the monochrome group is insufficient.

solution: 1. reduce the thickness of the ink layer; 2. increase the curing power of V U drying device; 3. reduce the machine speed, increase the ink curing time, can use monochrome multi-station curing; 4. In the process design to avoid ink layer overprinting as much as possible, can be used graphics edge color expansion side by side printing process; 5. Increase the power of the corona treatment device, improve the surface tension of the printing material, make the ink easier to dry adhesion, thereby increasing the ink adhesion fastness; 6. Use fast curing ink or increase the photosensitizer (desiccant) in the ink.

Failure 5: Paper Material Falling

reason: the quality of the paper itself is poor, and the surface coating is easy to drop powder due to low firmness; The wet environment or the problems of the material itself make the surface strength of the coating of the printing material lower or the ink viscosity is too high, which can easily cause powder failure. In addition, the powder drop is also related to the press side of the label.

solution: 1. select high-quality printing materials, especially when large-area field printing; 2. Reduce the viscosity of the ink, requiring the viscosity of the printing ink used in each color sequence to decrease in turn; 3. Improve the storage environment and printing environment of materials, reduce the environmental humidity; 4. Change the field printing to flat screen printing in the process design; 5. Before formal printing, use empty paper for preprinting to remove some floating powder; 6. Change the imprinting method of printing equipment to reduce the printing contact area.