Industry News

Lamination refers to bonding a plastic film coated with adhesive to flexographically printed labels such as vitamin medical bottle labels and perfume cosmetic bottle labels using a flexographic printing machine. This process involves heating and pressurizing the film to create a paper-plastic composite label product. It is one of the most important processes in the post-flexographic printing of substrates. It effectively enhances the quality and value of printed labels such as thermal printer label paper and Thank You sticker labels. However, lamination is not as simple as it seems; problems such as lamination wrinkles can easily occur if not handled carefully. This article will reveal the secrets of lamination wrinkling to label manufacturers, covering identification methods, causes, and solutions.

Flexo Press for Trademark Labels

How to Check Lamination Wrinkles

Advertising stickers, QR code labels, shipping stickers, thermal labels, gold foil shampoo stickers, and other labels exhibit a variety of wrinkling patterns. Among these, vertical wrinkles, diagonal wrinkles, horizontal wrinkles, deformed wrinkles, and wavy edges are the most common.

Vertical Wrinkles

Excessive tension during film lamination prevents the film from unfolding flat, resulting in creases. This causes wrinkles on products such as plastic bottle label stickers, food packaging label stickers, and water bottle labels after lamination. To resolve this, loosen the film tension appropriately and adjust the stretching rollers to allow the film to flatten before lamination.

Diagonal Wrinkles

When the film tension is high or the roller position is incorrect, the film tension will be inconsistent, resulting in uneven film transfer and a regular wrinkling towards the looser side. This problem can be solved by relaxing the film tension, adjusting the stretching roller, or temporarily replacing the film.

Flexographic Press for Drinking Water Bottle Labels

Lateral Wrinkles

When the heating roller temperature is too high or the rubber roller pressure is too high, lateral wrinkles will appear on the film during pressing. In this case, the roller temperature should be appropriately reduced or the rubber roller pressure should be decreased.

Deformation and Wrinkling

Excessively high temperatures during heating can cause the film to deform and wrinkle. Insufficient gap between the guide rollers can also cause wrinkles to be squeezed out of the film before pressing. Lowering the temperature and properly adjusting the gap between the guide rollers can effectively reduce or prevent wrinkles.

Wavy Edges

If the film is unevenly stretched at both ends or the adhesive layer is too thick, resulting in excessive viscosity, the paper and film may slip after pressing and squeezing, causing wavy edges. To avoid this, replace the film with a suitable one, adjust the amount of adhesive applied, and increase the drying temperature.

Label Printing Machine for Hot Stamping Clear Gold Foil Stickers

Why Lamination Wrinkles

There are many reasons why flexographically printed labels such as water stickers, juice drink beverage stickers, and wine beer bottle labels wrinkle when they are laminated, including environmental factors, material factors, pressure factors, and roller factors.

Environmental Factors

Excessive humidity in the factory workshop causes the paper to become damp and develop wavy edges, resulting in wrinkles during lamination; excessively high temperatures during lamination cause the paper to tighten at the edges, thus causing wrinkles.

Material Factors

Besides the paper itself, unevenness of the laminating material, uneven coating, or material shrinkage can also lead to wrinkles during the lamination process.

Flexographic Printer for Spice Bottle Food Labels

Pressure Factors

Excessive or insufficient lamination pressure, tension, or tensile force can all lead to wrinkles during the lamination process. For example, excessive pressure will increase lamination tension, causing localized shrinkage, while insufficient pressure will cause the lamination to lose contact, forming air bubbles on the surface.

Rubber Roller Factors

Uneven rubber rollers or contaminants on the rollers can easily cause wrinkles during the lamination process.

Other Factors

During the lamination process, issues such as accidental paper feeding misalignment or mismatched feed speeds can also cause wrinkles in the lamination.

Flexographic Machine for Brown Paper Sticker Labels

How to Prevent Lamination Wrinkles

To avoid wrinkling during lamination, we can address issues related to temperature, humidity, materials, pressure, and rubber rollers.

Temperature

If it's a temperature issue, adjust the temperature and try again, as different coating materials have different temperature requirements.

Humidity

If the problem is humidity, you can use appropriate equipment to humidify or dry it.

Flexo Printing Machine for Waterproof Label Stickers

Materials

If the problem is with the materials, such as damp paper, replace the damp paper or dry it with a hairdryer; if the problem is with the laminating material, try replacing it with a new roll of material.

Force

If the problem is with pressure, tension, or tensile force, try adjusting the corresponding parameters and pay attention to some details, such as ensuring the correct fabric wrapping direction after adjusting the pressure to avoid uneven tension, and maintaining a reasonable surface coating thickness to ensure uniform surface coating without local thickness differences.

Rubber Rollers

If the problem is with the rubber rollers, first check if there are any foreign objects on them. Wipe them carefully and repeatedly several times, and keep them clean regularly. If the problem is with the rubber rollers themselves, such as if they have been used for too long or are too old, consider grinding them down or replacing them with new ones.

Flexo Presses for Barcode Shipping Adhesive Labels

While the lamination technology of flexo printing machinery plays a crucial role in improving the quality of labels such as luxury logo stickers, cosmetics vinyl labels, and water bottle labels, the complexity of the process also presents numerous challenges for label manufacturers. Through in-depth analysis ofmineral the lamination wrinkling problem, we can not only master effective diagnostic methods but also gain a deeper understanding of its causes and find practical solutions.