Slit Hook Strips for Enhanced Peel Strength
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Solution Overview
Problem
Existing hook and loop fastening systems in disposable absorbent articles, such as diapers, often have low peel strength, leading to concerns about the reliability of attachment and potential inadvertent separation during use.
Innovation Solution
A hook strip with slits in the backing between rows of hook elements, including interrupted and partial slits, which enhances the peel strength by creating bridging regions that increase the area under the peel curve and allow for greater interaction with loop material without damaging it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional hook strip without slits is used, then the structure is simple and easy to manufacture, but the peel strength is low leading to unreliable attachment
Solution Approach 1:
The backing is divided into multiple segments by introducing slits between rows of hook elements. These slits create separate regions that can interact with loop material independently, increasing the total contact area and improving peel strength. The segmentation allows each region to contribute to the overall attachment force, resolving the contradiction between structural simplicity and peel strength.
Solution Approach 2:
The slits extend in the machine direction (length dimension) of the backing, creating a new dimensional feature that increases the interaction area with loop material. This dimensional addition transforms the flat backing into a multi-region structure that engages loops along its length, thereby improving peel strength without significantly complicating the basic strip geometry.
2Reliability
If the peel strength is increased through design modifications, then the attachment reliability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The backing is divided into multiple segments by introducing slits between rows of hook elements. These slits create separate regions that can interact with loop material independently, increasing the total contact area and improving peel strength. The segmentation allows each region to contribute to the overall attachment force, resolving the contradiction between structural simplicity and peel strength.
3Reliability
If the hook strip peels easily, then the user can remove it conveniently, but the attachment appears unreliable and may separate inadvertently during use
Solution Approach 1:
The slits segment the backing into multiple interaction regions that engage with loop material distributed along the length of the strip. This distribution of engagement points means that separation requires overcoming the combined resistance of multiple hook-loop interactions simultaneously, thereby improving perceived reliability while still allowing user-initiated removal.
4Strength
If more hook elements are added to increase attachment strength, then the peel strength improves, but the risk of damaging loop material increases
Solution Approach 1:
The slits create distinct interaction zones that distribute the engagement force across multiple separated regions. This distribution prevents concentration of stress on any single loop element, reducing the likelihood of loop material damage while maintaining high overall peel strength through the cumulative effect of multiple engagement points.
Solution Approach 2:
Each segmented region created by the slits can interact with loop material in a controlled local manner. The local engagement in each region is optimized to provide sufficient attachment force without excessive stress concentration, thereby preventing loop damage while achieving high overall peel strength through the cumulative effect of multiple regions.
Data Source
Figure 1~1B
Figure 2~2B
Figure 3~4A
AI summary
A hook strip is provided having a backing with a first surface and a length in a first direction; multiple rows of hook elements aligned in the first direction and projecting from the first surface of the backing; and slits in the backing between at least some pairs of adjacent rows of the hook elements. The slits may be interrupted by a bridging region of the backing, or the slits may be partial slits that penetrate the thickness of the backing in a range from 40 to 90 percent. A fastening laminate that includes a carrier and the hook strip described above joined to the carrier is also provided. In some embodiments, the fastening laminate includes slits that form separate, abutting portions of the backing on the carrier. An absorbent article containing the hook strip and a method of making the hook strip are also disclosed.