Hot melt adhesives for label application play a critical role in the packaging of fast-moving consumer goods (FMCG), particularly in bonding labels for plastic bottles in industries such as beverages and personal care. Taking well-known plastic bottled products as an example, the adhesion between the outer packaging paper and the bottle body heavily relies on high-performance hot melt adhesives. The substrates involved are typically polyethylene (PE), polyester (PET), or polypropylene (PP) plastic bottles paired with plastic film labels of corresponding materials. These applications impose two stringent requirements on hot melt adhesive performance:

1. Temperature Resistance

• High-Temperature Stability: During transportation, products may encounter elevated temperatures, requiring the adhesive to remain stable without flow, loss of adhesion, or oozing.

• Low-Temperature Flexibility: In cold storage environments, the adhesive layer must retain flexibility to prevent brittleness or delamination due to temperature drops.
  To meet these dual demands, the adhesive formulation must strike a precise balance in performance across temperature ranges. This is achieved by selecting optimal polymer matrices and additives that ensure structural integrity at high temperatures and elasticity at low temperatures.

2. Application Process
The "strip coating" process for label adhesives demands high precision, requiring continuous and uniform application on high-speed production lines. The hot melt adhesive must exhibit low melt viscosity and excellent thixotropy to ensure smooth application without stringing, which could compromise label aesthetics or equipment efficiency. Notably, in scenarios requiring optical clarity, colorless and transparent adhesives are preferred to maintain the label's visual appeal.

Practical Considerations

• Temperature-Speed Coordination: Adjusting the application temperature and production line speed is crucial. Adhesives with lower melt viscosity can minimize stringing through temperature optimization, while die temperature adjustments refine coating quality.

• Line Speed-Adhesive Volume Matching: Balancing line speed with adhesive application volume is essential to ensure bond strength while avoiding oozing or delamination.

As sustainability becomes a priority in the industry, next-generation hot melt adhesives that combine high performance with eco-friendly properties are emerging, driving label bonding technology toward greener and smarter solutions.