Apertured Web with Corrugated Grooves and Interlocking Teeth
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Solution Overview
Problem
Existing methods struggle to produce apertured webs with closely-spaced, wider apertures in the cross-machine direction, leading to issues like elongated apertures, low open area, and increased stress concentrations, which result in tearing, especially when using rotary knife aperturing or hot-pin aperturing techniques. Additionally, post-ring-rolling processes can weaken the web and misalign aperture sizes, making it difficult to achieve a registered corrugated pattern with alternating ridges and grooves.
Innovation Solution
A process and apparatus that apertures and stretches the web in a single step, using intermeshing rolls with specific tooth geometries to create discrete, closely-spaced apertures with larger widths in the cross-machine direction, while maintaining a corrugated structure with apertures in the grooves, enhancing web strength and registration precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If rotary knife aperturing is used to space aperture rows close together, then aperture row spacing is reduced, but aperture width in cross-machine direction becomes insufficient and apertures become elongated
Solution Approach 1:
The invention changes the geometric parameters of the aperturing teeth, specifically using teeth with a larger included angle (greater than 60 degrees, preferably between 90-120 degrees) compared to conventional teeth. This parameter change allows for closer aperture row spacing while maintaining adequate aperture width in the cross-machine direction and preventing elongation, thereby resolving the contradiction between reduced spacing and maintained aperture shape.
2Area of stationary object
If activation teeth with very small included angle are used, then aperture row spacing is reduced, but aperture width in cross-machine direction remains insufficient
Solution Approach 1:
The invention inverts the conventional approach by using activation teeth with a larger included angle (greater than 60 degrees) instead of the traditionally small included angle. This parameter reversal enables the system to achieve closer aperture row spacing while simultaneously maintaining sufficient aperture width in the cross-machine direction, resolving the contradiction between reduced spacing and adequate aperture width.
3Length of moving object
If post ring-rolling is used to stretch the web, then web stretching is achieved, but aperture alignment is lost and web strength is reduced
Solution Approach 1:
The invention merges the aperturing and stretching operations into a single integrated process step. The aperturing teeth are designed to simultaneously create apertures and stretch the web in the machine direction within the same operational pass, eliminating the need for subsequent post-ring-rolling. This integration maintains precise aperture alignment while achieving the required web stretching, thereby resolving the contradiction between web stretching and aperture alignment.
4Ease of manufacture
If conventional aperturing methods are used, then apertures are created, but stress concentrations increase leading to tearing
Solution Approach 1:
The invention changes the aperture geometry parameters by creating apertures with more uniform dimensions and reduced aspect ratios through the use of teeth with larger included angles. This results in apertures that are less elongated and more uniformly shaped, which reduces stress concentration at aperture edges and prevents tearing, thereby resolving the contradiction between ease of aperture creation and web strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in apertured webs with higher open areas, reduced aspect ratios, and improved strength in the cross-machine direction, preventing tearing and allowing for a registered corrugated pattern, which enhances fluid handling and breathability in absorbent articles.
Implementation Method 1
A process and apparatus that apertures and stretches the web in a single step, using intermeshing rolls with specific tooth geometries to create discrete, closely-spaced apertures with larger widths in the cross-machine direction
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
Corrugated and apertured web materials are disclosed. More specifically, the webs comprise alternating ridges and grooves, wherein apertures are located in the grooves. In one embodiment, a web comprises alternating ridges and grooves as well as alternating regions of lower basis weight and higher basis weight. The higher basis weight regions are located in the ridges and grooves and the lower basis weight regions are located in the sidewalls between the ridges and grooves. The higher basis weight regions located in the grooves comprise apertures. The apertures have greater open area than previous apertures in similar webs.