Apertured Nonwoven Web Structure for Wrinkle-Resistant Converting
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Solution Overview
Problem
Nonwoven webs used in absorbent articles face challenges in maintaining robustness during manufacturing processes while ensuring softness and functional performance, particularly in carded through-air bonded materials, which are prone to wrinkling and folding due to poor tensile properties.
Innovation Solution
A nonwoven web with apertures defined by side walls less than 460 µm in height and a Fiber Segment Orientation Index (FSOI) less than 0.46, produced using a method involving a pair of rolls with pins and recesses to create apertures, with a drawing ratio of at least 1.06, enhancing fiber segment orientation in the machine direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the nonwoven web is made softer to improve skin comfort and garment-like appearance, then the softness and aesthetic quality improve, but the tensile strength decreases causing wrinkling and folding during converting processes
Solution Approach 1:
The patent changes the geometric parameters of the aperture structure, specifically limiting the side wall height to less than 460 μm and controlling the Fiber Segment Orientation Index to less than 0.46. These parameter changes allow the nonwoven to maintain softness while improving tensile strength by preventing excessive fiber deformation and maintaining structural integrity during converting processes.
Solution Approach 2:
The patent creates local variations in the nonwoven structure through controlled apertures with specific side wall heights and fiber orientations. The aperture regions provide localized flexibility and softness while the surrounding fiber matrix maintains overall tensile strength, allowing different regions of the same material to fulfill different functional requirements.
2Strength
If the nonwoven web structure is modified to improve tensile strength and reduce wrinkling, then the robustness to converting processes improves, but the softness may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aperture side wall height (less than 460 μm) and Fiber Segment Orientation Index (less than 0.46). These controlled changes optimize the balance between tensile strength and softness, ensuring the nonwoven maintains both robustness during converting and comfort during use.
3Strength
If aperture side wall height is increased to improve structural integrity, then the tensile strength improves, but the softness and comfort properties deteriorate
Solution Approach 1:
The patent implements a specific parameter threshold for aperture side wall height (less than 460 μm) that optimizes the balance between structural integrity and softness. This parameter change ensures that the apertures provide sufficient structural support while maintaining the compressibility and conformability needed for skin comfort.
4Strength
If the Fiber Segment Orientation Index is increased to improve tensile strength, then the robustness to converting processes improves, but the isotropy and uniformity of the nonwoven structure decrease
Solution Approach 1:
The patent controls the Fiber Segment Orientation Index to be less than 0.46, maintaining a balance between tensile strength and isotropy. This parameter control ensures sufficient fiber orientation for strength while preserving the uniform random distribution characteristic of carded nonwovens, maintaining compositional stability.
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 provides increased tensile strength and robustness to converting processes, reducing wrinkling and folding, without compromising softness or increasing material cost or basis weight.
Implementation Method 1
using the nip between the pair of rolls, creating apertures in the precursor web to thereby produce the nonwoven web
Implementation Method 2
the feed rate is different from the take-off rate, and the take-off rate divided by the feed rate defines a drawing ratio of at least 1.06
Implementation Method 3
enhancing fiber segment orientation in the machine direction
Data Source
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AI summary
A nonwoven web with apertures, suitable for use in a disposable absorbent article, is disclosed. Also disclosed is a method of producing a nonwoven web with apertures. The nonwoven web comprises greater than 50%, by weight of the web, of thermoplastic fibers. Each aperture is defined by an opening in a first surface of the nonwoven web and a side wall. The side walls of the apertures have a mean height of less than 460 μm. Also disclosed is an absorbent article comprising the nonwoven web. A topsheet, backsheet, or other component of the absorbent article may comprise the nonwoven web.