What should I do if bubbles occur during the production of protective film?

Protective film is a common die-cutting material in die-cutting production, but I believe that many protective film manufacturers sometimes have air bubbles during the production process, which is very troublesome.

main reason

Poor film wettability

The main reason : the slip agent and antistatic agent added by the manufacturer when manufacturing the film slowly soak into the surface of the film during storage, which reduces the surface tension of the film; in addition, the corona treatment strength of the film during processing is not enough or If the storage time is too long, the decrease of surface tension is also an important reason for the poor wettability of the film.

Low temperature leads to poor wetting

Main reason : As the main agent of the adhesive agent drops in liquid temperature due to low temperature, the viscosity of the prepared glue increases and the wettability is poor; due to the influence of low temperature on the film, the poor flow of the glue after coating causes blockage and poor wettability.

Insufficient coating

The main reason : the glue viscosity is too high or too low when coating, causing insufficient coating.

glue bubbles

The main reason : the temperature of the Drying Oven is too high, and the glue foams.

Solution

(1) Choose the right ink and increase the amount of coating. The selection of dry composite white ink is especially important, and its influence is multifaceted;

(2) Enhance the wettability of the glue to the film, improve the defects of poor local gluing; increase the amount of coating; increase the temperature and pressure of the composite roller, use a smooth roller; reduce the composite speed to increase the soaking time and gluing time; Well wet glue and preheated;

(3) Preheat the glue and film and increase the temperature of the composite pressing roller;

(4) Clean the coating roller, and strengthen the management of coating volume and coating roller. For coating rollers, generally new rollers need to be aluminum-plated after being used to 5 millIon Meters (5000R/S), and then re-engraved after 3 times of chrome plating. Such management can prevent poor appearance of the house caused by insufficient coating rollers and the problem of low peel strength. Eliminate static electricity on the film and pay attention to keeping the machine environment hygienic. The adhesive solvent is completely sealed and stored and filtered during use;

(5) Adjust the viscosity, replace the coating roller, and meet the requirements of the coating amount through the cooperation of the glue solid content and the coating roller within the viscosity range that meets the process requirements;

(6) Adjust the drying conditions. Small air volume is likely to cause solvent residues. Generally, the wind speed at the nozzle of the drying box needs to reach 30-35 m/s. -80°C, the temperature of the inlet section I should not exceed 60°C;

(7) Increase the amount of coating and the temperature and pressure of the composite pressing roller, increase the rubber hardness of the pressing roller, and increase the rubber hardness of the pressing roller to between 80-85°C. And adjust the "wrap angle" angle of the film that is introduced into the front of the pressure roller, and enter the composite roller in the tangential direction as much as possible;

(8) Take moisture-proof measures, such as avoiding moisture-absorbing materials such as nylon and cellophane to react with NCO groups to produce CO2 after absorbing moisture, keep the environment dry, and seal the packaging materials with curing agents;

(9) Increase the amount of coating used to make the protective film and the temperature and pressure of the composite pressing roller, increase the rubber hardness of the pressing roller, and increase the rubber hardness of the pressing roller to between 80-85°C. And adjust the "wrap angle" angle of the film that is introduced into the front of the pressure roller, and enter the composite roller in the tangential direction as much as possible;

(10) Taking moisture-proof measures during the forming process of the protective film, such as keeping the environment dry, curing agent to seal the packaging material, etc., can also have a certain effect on improving the problem of air bubbles, thereby greatly improving the quality and use effect of the protective film.