Industry News

In summer, the temperature is high and the humidity is high. Water labels, beer labels, vitamin medical bottle labels, thank you sticker labels and other self-adhesive labels often encounter many problems in the flexographic printing process, which brings a lot of troubles to self-adhesive label manufacturers such as trademark labels, advertising stickers, QR code labels, gold foil shampoo stickers, etc. This article will focus on the causes and solutions to problems such as material deformation, edge glue overflow, and label lifting, hoping to help self-adhesive label manufacturers.

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Material Deformation

In summer, we often encounter the problem of raw materials being loose or tight. This problem often occurs when the raw materials are taken out of the warehouse after being placed for a period of time and found to be loose, and some serious ones are even unusable. This is because the humidity in the air changes greatly in summer, and the tension of the self-adhesive material changes after losing or absorbing water, causing the raw materials to be loose or tight. Some materials, especially thermal labels, waybill barcode stickers, luxury cosmetics labels, mineral water bottle labels and other film-based self-adhesive materials, are found to have bulging cores when they are used. This is also the reason.

MJRY Series Stack Type Flexo Printing Machine for Luxury Cosmetics Labels

Therefore, in summer, we should try to keep the minimum inventory of self-adhesive materials, reduce the inventory cycle, strengthen warehouse management, and achieve "first in, first out". Generally, the materials will not change significantly within 7 to 10 days after arrival, and the longest time should not exceed 15 days. At the same time, the ambient temperature of the self-adhesive label materials used to make food packaging label stickers, drinking water bottle labels, and high grade matt finish label stickers should be controlled at 18~28℃ and the humidity should be controlled at 40%~60%. It should be noted that the self-adhesive label materials that have not been processed on the machine should not be opened in advance, and the self-adhesive label materials that have not been used up or the self-adhesive label materials that need to be processed in the next process should be sealed and stored in time.

Edge Glue Overflow

We know that the glue layer in products such as spice bottle labels, food jars cans sticker labels, shipping stickers, , etc. has a certain fluidity and is greatly affected by temperature. Generally speaking, the higher the ambient temperature, the stronger the fluidity of the glue. Once the fluidity of the glue becomes stronger, it is easy to overflow the glue.

When the self-adhesive label material is cut, due to the difference between the cutting blade and the back of the knife, one side of the end surface of the cut self-adhesive material has a certain stickiness when touched by hand. If it is affected by high temperature, the two sides of the self-adhesive label material are more likely to have glue overflow problems.

Die-Cutting Unit in Inline Type Flexographic Printing Machine for Soap Label Stickers

Once the self-adhesive label material overflows, it will be very troublesome to deal with it. Because the overflowing glue will stick to the material of the lower layer, making it impossible to unwind and flexo print the material normally. Therefore, when storing the self-adhesive label material, or when the unused self-adhesive label material is stacked together, the two sides of the self-adhesive label material can be separated by release paper to avoid the rolls from being unable to be separated due to adhesion. It should be noted that the silicone oil surface of the release paper should be in contact with the end face of the material, and the stacking should not be too high, otherwise it is easy to cause overflowing glue. In addition, household daily chemical labels, waterproof vinyl sticker labels and other self-adhesive label materials can be sprayed with oil-based or neutral release agent on the material edge before flexographic printing and die-cutting to reduce the glue overflowing from the material edge and remaining on the rubber roller. If the self-adhesive label material has serious overflowing glue, it needs to be edge trimmed again before use.

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Label Lifting

When die-cutting self-adhesive materials in summer, if the ambient temperature is high, it is easy to have labeling and glue overflow during waste discharge, especially for hot melt adhesive labelstock. This is because hot melt adhesive exhibits longer stringing than water-based adhesive. When die-cutting and discharging waste, it always feels that the glue layer is not completely cut off, the wire drawing is obvious, and the glue flows back, resulting in waste discharge with labeling and glue overflow.

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Therefore, when using hot melt adhesive labelstock for die-cutting and printing in summer, the temperature of the production site should be controlled at around 23°C as much as possible. The waste can be discharged directly after die-cutting, or the number of rollers through which the material passes can be reduced as much as possible to reduce glue reflux. At the same time, try to use a die-cutting knife with a special coating on the surface when die-cutting. In particular, low-temperature glue and Freezer adhesive label materials have particularly strong fluidity under high temperature conditions. Generally, there will be slight glue overflow under processing conditions, and the requirements for the processing environment are high. If necessary, the self-adhesive label material can be frozen before processing.

Die-Cutting Unit in Inline Type Flexo Presses for Transparent Logo Stickers

In summer, when flexo printing self-adhesive labels such as cakes jelly labels, self-adhesive gift tags, Christmas stickers, waybill packaging sticker rolls, etc., problems such as material deformation, edge glue overflow and label lifting are common challenges faced by manufacturers. These problems not only affect the appearance and quality of the labels, but may also lead to reduced production efficiency, machine failure, and increased costs. By reasonably selecting materials, optimizing the flexo printing process, controlling the flexo printing environment temperature, and strengthening storage and transportation management, these problems can be effectively avoided to ensure the production quality and efficiency of self-adhesive labels.