What are the white spots on the protective film? How to reduce the impact of the white spots of the protective film on the product?

The protective film is covered with a layer of oily glue on the base of the bottom mold. It is a high-end protective film product in the protective film industry, and its use is mainly for high-end batteries and lenses. For the packaging of panel products, especially for products that need to be insulated from water, air and sunlight, electronic protective film has become their first choice for packaging.

There are not many white spots on the protective film. Some are caused by the production process, and some are caused by improper storage after production. In short, the white spots have caused great losses to the product itself, so how to eliminate these white spots, For protective film manufacturers, it is all necessary knowledge.

So how to reduce the impact of the white spots of the protective film on the product? Remind everyone to pay attention to the following points:

1. The adhesive should be thoroughly dried

Because the barrier property of aluminum plating is better, if the bonding in the composite film is not completely dried, then after the composite film enters the maturation room, a large amount of residual solvent needs to be released quickly, and bubbles will inevitably form under the barrier of the electronic protective film. There may even be no white spots when the machine is off, but white spots appear after maturing.

2. Viscosity of glue liquid and number of screen rollers

There is a certain matching relationship between the viscosity of the glue liquid and the number of lines of the screen roller. If the matching interval is too large, the coating state of the glue will be damaged, and the occurrence of "white spots" is more concerned.

3. Adopt special adhesive for electronic protective film

The surface tension of the special adhesive for electronic protective film composite is low, and the coating and spreading effect on the surface of the glue layer is obviously better than that of the general-purpose adhesive. The use of glue will make it easy to control the leveling of the glue and have an ideal coating state. In terms of the adhesive coating state alone, the use of electronic glue can eliminate the possibility of white spots.

4. Adopt electronic protective film coating method

The usually used coating process is printing film (ink surface) gluing. A special coating method is used here to avoid the problem of uneven penetration of the ethyl ester into the ink layer. At the same time, the coated adhesive can fully and evenly cover the glue. Layer surface, so that white spots can be eliminated well, but this process has its big limitations. First, it is only limited to the compounding of VMPET, and other electric protective films are affected by heat in the oven under the action of tension. , It will stretch and deform; secondly, it will sacrifice a certain amount of peel strength.

5. Correct coating roller cleaning method

Flexible packaging companies must adhere to the regular cleaning system of the coating roller and master the correct cleaning method of the coating roller. When producing full white or light background printing film, two points should be paid attention to. First, the doctor blade, coating roller, and flattening roller should be thoroughly cleaned before production.

With the rapid development of smart products, the popularization and application of smart products such as smart phones and smart TVs has greatly promoted the rapid development of the decoration industry, especially the protective film industry. However, when the protective film is attached, the protective film will often appear dark, so what are the reasons for the dark shadow of the protective film? Here is a brief introduction for everyone.

1. The longer the time, the greater the possibility of formation

The longer the time passes, the larger the contact surface between ordinary small bubbles and the air, and the higher the possibility of forming dark shadows. Therefore, try to avoid the generation of small bubbles when applying the film, and use a good-quality protective film with uniform glue to delay the appearance of dark shadows.

2. Emulsifier

After the emulsifier migrates, dark shadows will be produced, and the surfactant will act as an external plasticizer in the coating film, making the coating film soft and elastic. During coating, it is advantageous if the plasticizer is uniformly distributed. However, due to the surface activity of the surfactant, the molecules will migrate out of the bulk, gather on the surface, and tend to be concentrated on the air interface, thus forming a dark shadow.

3. Temperature

When the protective film is at a temperature of 80°C, it is lifted up due to bubbles, that is to say, the protective film has begun to be torn slowly at high temperatures, if the thermal resistance or cohesion of the protective film adhesive is not good. , It is easy to have residual glue or shadow around the bubble of the protective film. Generally, the place where the shadow appears is the place where the bubble of the protective film is formed.