The use of structural adhesives is critical in the manufacturing of sanitary napkins; both the application process and material selection directly impact product safety and user experience. The following are key precautions that require particular attention when utilizing structural adhesives specifically designed for sanitary napkins:
Select Specialized Hot-Melt Pressure-Sensitive Adhesives That Comply with Hygiene Standards
It is imperative to select hot-melt pressure-sensitive adhesives (such as those based on EVA or SIS) that have obtained medical-grade or food-contact-grade certification. This ensures the absence of harmful substances-such as formaldehyde, heavy metals, and migratable fluorescent whitening agents-and guarantees compliance with the standards outlined in *GB 33372-2020: Limits of Harmful Substances in Adhesives* and *GB/T 8939-2018: Sanitary Napkins (Panty Liners)*.
Strictly Control Application Temperature to Prevent Material Damage
The operating temperature is typically set within the range of 110–160°C; however, the specific temperature-and whether to use a low-temperature or high-temperature adhesive-should be selected based on the characteristics of the substrate material. For instance, when working with heat-sensitive materials such as PE film, it is advisable to utilize a low-temperature structural adhesive (110–130°C) to prevent scorching the film, which could otherwise lead to deformation or nozzle clogging caused by carbonization.
Precise Control of Coating Process Parameters:
Coating Method-It is recommended to employ dot, grid, or spiral adhesive application patterns to minimize adhesive usage and enhance breathability. Coating Weight-Avoid excessive thickness, which can result in a sensation of stiffness or adhesive transfer, thereby compromising comfort and peel performance. Open Time-Ensure that bonding is completed before the adhesive cools; an excessively short open time can easily lead to insufficient bond strength.