The backsheet is typically made of a water resistant material, such as plastic, which makes the backsheet more vulnerable to damage, than for example a nonwoven web. In addition to harming the appearance of the absorbent article, damage to the backsheet can compromise the effectiveness of the absorbent article. In fact a damaged backsheet could allow absorbed fluids to leave the absorbent article and contact the skin or clothes of a wearer.
Deep channel embossments in an absorbent article provide improved fit of the absorbent article to the wearer's body, which is important in delivering superior protection performance. Deep channel embossments also provide a pleasant feminine design to the wearer. Further the embossed region also serves as a fluid barrier that prevents fluid from running off to the side of the absorbent article. In addition, the process of forming deep channel embossments can produce embossment regions, not only in the surface contacted by the rotary embossing rolls (typically the body facing surface including the topsheet), but also in the opposing surface (typically the garment facing surface). The garment facing surface of the absorbent core is the surface that will come in contact with the backsheet. The backsheet will often conform to the embossments present in the garment facing surface of the absorbent core, resulting in an uneven surface in the backsheet.
The uneven surface of the backsheet causes problems when trying to attach release paper to the surface of the backsheet. Adhesive is usually applied to the release paper first and then the release paper is contacted with the backsheet, such that the adhesive holds the release paper to the backsheet until use. However, as there are valleys present in the backsheet due to the embossments the adhesive present on the release paper will bridge these valleys, and consequently the adhesive will not come into direct contact with the backsheet. The irregular adhesive contact leads to several problems, including poor adhesive transfer from the release paper to the backsheet allowing adhesive to remain on the release paper or reducing its effectiveness of remaining on the absorbent article and transferring to an undesired surface, such as a users panties.
Another typical issue of rotary embossing process is the difficulty to have even embossing. Embossing depth depends on die pressure. Since what is applied on a die is a force you have to be sure to have a constant surface in contact with absorbent product to produce a constant pressure and carry out an even depth embossing.
Finally 2 recommendations for this process: proper embossing design and its right location along the machine process.