The Common Problems in Dry Laminating Processing

Inadequate Surface Treatment: If the surface of the substrate is not properly treated, such as having contaminants, grease, or low surface energy, the adhesive may not bond well. For example, plastic films that have not undergone corona treatment may have poor adhesion with the adhesive.

Improper Adhesive Selection: Different substrates require specific types of adhesives. Using the wrong adhesive may lead to poor adhesion. For instance, an adhesive suitable for bonding paper may not work well on plastic films.

Incorrect Adhesive Application: Issues like insufficient adhesive application, uneven spreading, or improper drying conditions can all result in poor adhesion. If the adhesive is not dried completely, its bonding strength will be affected.

Air Entrapment: During the laminating process, air can get trapped between the layers. This often happens when the laminating speed is too fast or the pressure is not evenly distributed, preventing the air from being completely expelled.

Solvent Evaporation: If the solvent in the adhesive does not evaporate completely before laminating, it can form bubbles as it evaporates later. This is more likely to occur in high-humidity environments or when the drying conditions are not properly controlled.

Substrate Moisture: Moisture present in the substrate can also cause bubbles. When the substrate is exposed to high humidity or has not been stored properly, the moisture can vaporize during the laminating process and create bubbles.

Uneven Tension: If the tension applied to the substrates during laminating is not uniform, it can cause wrinkling. This may be due to improper adjustment of the tension control system or differences in the mechanical properties of the materials.

Thermal Expansion Mismatch: Different materials have different coefficients of thermal expansion. When exposed to heat during the laminating process, the difference in expansion can lead to wrinkling. For example, laminating a plastic film with a paper substrate may cause wrinkling if the temperature is not controlled properly.

Substrate Thickness Variation: If the substrate has thickness variations, it can result in uneven pressure distribution during laminating, leading to wrinkling. This is more common in materials like non-woven fabrics or some flexible packaging materials.

Thermal Degradation: High temperatures during the laminating process can cause thermal degradation of the substrates or the inks used, resulting in color change. This is especially true for heat-sensitive materials and inks.

Chemical Reaction: The adhesive or other components in the laminating process may react with the substrate or ink, causing a color change. For example, some adhesives may contain chemicals that can interact with the pigments in the ink.

UV Exposure: If the laminated product is exposed to ultraviolet (UV) light during or after the laminating process, it can cause photo-oxidation and color change. This is a common problem for products that need to be stored or displayed under UV light.