The reason why the most popular color packaging fi

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The reason why the film covering of color packaging is not bright

1 Improper temperature control

for different substrates, waste plastic particle treatment will become a hot development in the future. When coating, the temperature of the electrically heated steel drum must be adjusted according to the covered products. If the coated substrate is gold card paper, the temperature of the coated steel roller shall be controlled at 7080 ℃; if it is coated with 250g/m2 or 300g/m2 gray board paper, the temperature shall be adjusted to 80 ~ 90 ℃. Whiteboard absorbs more moisture than gold card paper during placement. Especially in rainy days and winter, if the temperature adjustment is not appropriate, the coated products will not be bright. When laminating, it is sometimes found that there are obvious water drops or steam on the silicon drum, which is caused by the paper absorbing a large amount of water. The coating temperature of such products must be increased for some of the most rugged ships. For the first batch of products, the temperature of the drying channel can be controlled at 50 ~ 60 ℃. Use the coated film to stick at the outlet of the electromagnetic interference drying channel with your fingers. There is no obvious trace, just a little sticky. If the coating temperature is too high, it will blister. Therefore, the temperature of the heating steel drum must be controlled according to the product characteristics

2. Insufficient pressure

according to the needs of customers, the thickness of substrate materials is mostly inconsistent. When laminating, the pressure between the silicone drum and the steel drum should be adjusted according to the thickness of the substrate paper. If the pressure is too small, the film of the coated product is not firm, not bright, and easy to wrinkle: if the pressure is too large, it will produce film wrinkle and paper deformation

3. Glue output

when using stretched polypropylene film for coating. The film must be glued. The amount of glue is applied to the moving film by a driving steel roller installed in the glue box. The amount of glue is controlled by a steel blade falling on the steel roller. Light pressure and large glue amount: heavy pressure and small glue amount. The amount of glue shall be well controlled, so that it can be covered firmly and evenly without crystal point. If the amount of glue is too large, the covered product will have no luster

in the process of gluing, special attention should be paid to prevent small particles and foreign matters after glue solidification from remaining in the glue tray. If there is any residue, it will be taken up by the upper rubber roller during rotation, and it will be stuck on the rubber blade, where a glue free white print will appear. Therefore, after a long-time shutdown of the laminating machine, before the laminating machine is started, it must be calculated by integrating) the laminating water or high boiling point kerosene is used to clean the glue pump and the glue bucket box, so as to ensure that the glue on the rubber roller is normally coated on the film without any trace

4. Keep the drum clean

after a long time of pressing, the steel drum will be in direct contact with the membrane. In addition, due to the effect of temperature, some debris will be left on the steel drum. The silica gel roller directly contacts with the back of the paper of the covered product. In addition, the separation of the paper feeding distance causes a lot of glue to be directly pressed on the glue roller to produce accumulation, which will affect the brightness of the covered product

in severe cases, the covered products will be wrinkled. Therefore, we must keep the drum clean and shut down at any time to ensure the quality of coated products

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