Analysis of the reason why the packaging film is not bright

Part of the color packaging film method is to use biaxially oriented polypropylene film, the product after the film will appear dull or blistering. The author conducted research and analysis on this issue and summarized the following points.

1 Improper temperature control

When laminating different substrates, the temperature of the electrically heated steel drum must be adjusted according to the coated product. If the coated substrate is gold cardboard, the temperature of the laminated steel cylinder should be controlled at 70 ℃ ~ 80 ℃: if it is coated with 250g / m2 or 300g / m2 gray whiteboard paper, the temperature should be adjusted to 80 ℃ ~ 90 ℃. During the placement of whiteboard paper, the moisture absorbed by it far exceeds that of gold cardboard. Especially in rainy days and winter, if the temperature is not adjusted properly, the film-covered product will not shine. When laminating, sometimes there are obvious water droplets or steam on the silicon roller, which is caused by the paper absorbing a lot of moisture. The film laminating temperature of such products must be increased a little bit more. For the finished product, the temperature of the drying tunnel can be controlled at 50 ℃ ~ 60 ℃. The glued film can be stuck on the exit of the drying tunnel with fingers without any traces, and it can be a little sticky. If the film temperature is too high, it will foam. Therefore, the temperature of the heating steel drum must be controlled according to the characteristics of the product when laminating.

2 Insufficient pressure

According to customer needs, the thickness of the substrate material is mostly inconsistent. When laminating, the pressure between the silicone roller and the steel roller should be adjusted according to the thickness of the substrate paper. If the pressure is too low, the film of the film-covered product is not strong, bright, and easy to produce wrinkles: too much pressure will cause film wrinkles and paper deformation.

3 glue output

When using stretched polypropylene film. The film must be glued. The amount of glue is applied to a moving film by a transmission steel roller installed in a plastic box through a rotating belt. The amount of glue is controlled by a steel blade that falls on the steel roller. Large amount of pressure light glue: small amount of pressure heavy glue. The amount of glue should be well controlled, which can be covered evenly and can not produce crystal points. If the amount of glue is too large, the covered product will be dull.

Special attention should be paid to the process of gluing, it is necessary to prevent the tiny particles and foreign objects after the gel is solidified from remaining in the rubber tray. If it is left, it will be picked up by the rubber roller during rotation and stuck on the rubber blade, and there will be a rubber-free white mark here. Therefore, after the laminator is shut down for a long time, before the laminator is turned on, the glue pump and the hopper box should be cleaned with laminating water or high boiling point kerosene to ensure that the glue of the upper roller is normally coated on the film and does not produce. Traced.

4 Keep the roller clean

After a long time of pressing, the steel drum is in direct contact with the membrane. With the effect of temperature, some residues will be left on the steel drum. The silicone roller is in direct contact with the back of the coated product paper, plus the separation of the paper distance, many glues are directly pressed onto the rubber roller to cause accumulation, which will affect the brightness of the coated product.

In severe cases, the covered product may wrinkle. Therefore, the drum must be kept clean and shut down at any time to ensure the quality of the film-covered product.

Our Polyethylene Film could be in high density polyethylene or low density polyethylene. It includes the lay-flat tubing, stretch wrap film fro industry, Fresh Film for household and Mulch Film. The films could be for industry or for household. Measurement, thickness, color, size of the roll and packing are depending on orders. 

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