Doing More With Less: Adhesive’s Role in Core
As market trends in disposable hygiene shift toward products that have less fluff and a thinner core, users are also asking for more out of product performance. How is it possible to create products that offer reliable leak protection, keep the skin dry, etc. when materials are removed from the core system? The answer lies within the adhesives used.
In thinner cores, adhesives take on additional properties that contribute more value than originally imagined. We like to call them smart adhesives. Within the core system, smart adhesives:
- Help prevent core shifting when applied to the topsheet and backsheet
- Anchor the acquisition distribution layer (ADL) to the topsheet and core
- Stabilize the fluff/SAP matrix when a core wrap is not used, and are critical for SAP stabilization when fluff is not used
- Seal the core wrap and bond adjacent materials to prevent shifting
But every adhesive isn’t created equal. And every adhesive doesn’t work in every core. Knowing your options can help build a smarter, thinner core that meets and exceeds performance expectations. Among the things to consider include:
A nonwoven wrap offers faster absorption but does not reduce the risk of core crack leakage. While a tissue wrap has slower absorption, active users stay drier with less rewet and more resilience to abuse.
Applying adhesive directly to the top of the core can impede overall core performance. Bottom core adhesive application increases the amount of abuse the diaper can take and speeds up absorption for better core performance.
With no negative correlation to acquisition or rewet and a positive impact on integrity, a wider application dispels the notion that more adhesive is a bad thing, as proven by results from comparing 2” and 3” adhesive applications. While reducing the width of the application pattern may decrease adhesive use and thereby cost, it also reduces core integrity and overall performance.
A spray method creates less contact area and can mean fewer drops and less resilience, which negatively impacts core performance. A multi-slot method offers more coverage and a thinner adhesive layer than spray delivers, enabling a core to withstand significantly more abuse.
The impact of changing from 2 grams per square meter (gsm) to 4 gsm add-on varies with the application method. There is no difference found between 2 gsm and 4 gsm add-on using the spray method. When using the multi-slot method, increasing add-on from 2 gsm to 4 gsm strengthens core integrity and enhances performance.
While every material in a disposable hygiene product plays an important role, the adhesive used to bond the components is critical to ensuring core integrity and performance.