Factors related to solvent residue after using flexible packaging polyurethane laminating adhesive
2026,07,02
The residual solvents in flexible packaging are mainly influenced by several factors. Here are some common factors:
1.The Influence of Compound Speed
Similar to the principle that printing speed affects the amount of solvent residue, the lamination speed is also a factor influencing the amount of solvent residue. Therefore, during production, the lamination speed should be reasonably set according to the drying capacity of the oven.
2. Influence of Laminating Adhesive Application Volume
The greater the application volume of the laminating adhesive, the greater the hindrance effect caused by the hardening of the adhesive surface layer on the evaporation of the inner layer solvent during the oven process, and the greater the final solvent residue will be. Therefore, on the basis of meeting the performance requirements of the flexible packaging products, the application volume of the adhesive should be controlled as much as possible.
3. Influence of Ethyl Acetate Moisture Content
The moisture in ethyl acetate affects the volatility of ethyl acetate, which in turn influences the solvent residue of the lamination membrane. Therefore, it is necessary to select ethyl acetate with higher purity.
4. Influence of Adhesives
Under the same substrate and process conditions, using different manufacturers' polyurethane laminating adhesives may result in different solvent residue levels in the final produced lamination film. This is because the molecular bonds of polyurethane adhesives contain active hydroxyl groups, which form hydrogen bonds with ethyl acetate, thereby hindering the volatilization of ethyl acetate. Changes in the main component of the laminating adhesives affect the strength of the hydrogen bonds. Stronger hydrogen bonds make it more difficult for ethyl acetate to be released, thus different laminating adhesives from different manufacturers will result in different solvent residue outcomes. Before choosing a laminating adhesives supplier, it is necessary to fully understand the main component of their laminating adhesives to avoid unnecessary difficulties in controlling solvent residue.
