Common Problems and Solutions of Packaging Bags

With the improvement of living standards, packaging bags can be seen everywhere in daily life, including various clothing packaging bags, electronic packaging, industrial product packaging bags, aluminum foil packaging bags and so on, with a wide variety of styles. A good packaging bag is also produced through production procedures and strict standards. So what problems will be encountered in the process of manufacturing and producing packaging bags? How should we solve them? Next, Zhitu Packaging will share with you!

packaging bag wrinkled

1. The thickness of the base material is uneven, and the difference between the films is too large.

2. The base material is skewed during unwinding.

3. When there is too much or a lack of glue, interlayer sliding will occur; uneven glue application can also cause local wrinkles.

4. The adhesive is not dry enough, there are too many residual solvents, and the adhesive force is small, causing the two substrates to shift after compounding.

5. The composite film is rolled directly without cooling or cooling, and the high-temperature soft composite film is easy to wrinkle.

6. Inappropriate setting of tension compound pressure.

7. Improper tension control, uncoordinated and mismatched tension between unwinding and winding.

8. The guide rollers are not parallel.

9. The appearance of each guide roller is not clean, with foreign objects sticking to it, or the appearance of the guide roller is uneven, with pits, scratches, bumps, etc.

Solutions

1. Replace the film with qualified quality.

2. Adjust the position of the film to prevent it from deviating during the conveying process.

3. Adjust the glue application amount and apply the glue evenly.

4. Adjust the process parameters to ensure the adhesive dries sufficiently and reduce the residual amount of solvent.

5. The composite film should be fully cooled before being rewound.

6. Adjust the lamination pressure.

7 Adjust the unwinding and rewinding tensions to match the tensions of each part.

8. Adjust the parallelism of each guide roller.

9. Clean the surfaces of each guide roller, replace damaged guide rollers, and ensure that the surfaces of the guide rollers are flat, smooth and clean.

Aluminum-plated packaging bags show mottling

1. Improper selection of adhesive: Common adhesives have poor affinity for the aluminum-plated layer and poor coating performance. If the coating is uneven, mottling will occur.

2. Excessive residual solvent in the adhesive liquid: After the printed film is laminated, the ink layer is moistened by the residual solvent in the adhesive liquid, which can cause mottling. 3. Insufficient hiding power of the ink: Especially for light-colored inks, light passes through the ink layer and is reflected back by the aluminum layer, resulting in mottling.

4. Insufficient glue application amount or uneven glue application, with air bubbles mixed in the composite film

Solutions

1. Use a special adhesive for aluminum-plated films.

2. Properly increase the drying temperature of the drying tunnel or appropriately reduce the composite line speed to ensure that the adhesive is fully dried.

3. Choose ink with strong hiding power or increase the thickness of the ink layer.

4. Appropriately increase the coating amount of the adhesive and check the condition of the rubber pressure roller to ensure uniform coating.

Sticky packaging bags

1. During the bag printing process, the drying speed of the ink is incompatible with the printing speed, resulting in some solvents still remaining in the ink layer after printing, which softens the ink layer and thus makes the composite film sticky as well.

2. The adhesive is not completely dried, and the residual solvent gradually penetrates into the ink layer, causing the ink layer to soften and become sticky.

3. The plasticizer in the plastic film migrates to the ink layer, causing the film to soften and become sticky.

Solutions

1. Adjust the drying speed of the ink according to actual conditions and ensure it is fully dried

2. Adjust the process parameters to ensure that the adhesive is fully dried and the residual solvent content is kept to a minimum.

3. Replace the plastic film

The packaging bag has "small pockmarks

1. There are impurities in the adhesive, there is too much dust in the air of the workshop environment, and there is also dust in the hot air blown out from the drying tunnel after gluing. The dust adheres to the adhesive layer and is sandwiched between the centers of the two base films during lamination.

2. The solvent of two-component reactive adhesives is prone to whitening and clouding due to temperature changes, leading to an increase in "small pockmarks".

Solutions

1. Filter the adhesive; keep the environment clean; clean the glue buckets and glue trays thoroughly; remove dust from the hot air at the air inlet of the drying tunnel with high-mesh filter screens or other filtering materials.

2. Do not use "cloudy white" adhesive agents.

The above are the common problems and solutions of packaging bags shared by the editor of Zhitu. Follow Zhitu packaging bags for more information!