Stitch-Bonded Loop Face Composite for Diaper Fastening
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Solution Overview
Problem
Existing hook and loop fastening systems in diapers face challenges in maintaining low air permeability when using nonwoven polypropylene spunbonded substrates, which affects the reliability of the vacuum system in diaper formation machines, while also failing to provide a fabric-like feel preferred by some users.
Innovation Solution
A stitch-bonded loop face composite material using a nonwoven substrate with an SMS construction, comprising layers of meltblown and spunbond fibrous materials, which maintains low air permeability and provides a fabric-like feel, suitable for use with diaper machine vacuum systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a nonwoven polypropylene spunbonded substrate is used in the loop face composite material, then a fabric-like feel is provided, but air permeability increases above acceptable levels affecting vacuum system reliability
Solution Approach 1:
The patent applies composite materials by combining multiple nonwoven layers (spunbond and meltblown polypropylene) with different properties. The spunbond layers provide fabric-like feel and strength, while the meltblown layers provide liquid barrier properties and help control air permeability. This composite structure resolves the contradiction by integrating materials that individually have conflicting properties into a unified substrate that achieves both fabric-like feel and acceptable air permeability for vacuum system reliability
Solution Approach 2:
The patent changes physical parameters of the substrate by controlling the weight, thickness, and composition ratios of different nonwoven layers. By adjusting these parameters, the substrate achieves optimal balance between air permeability (for vacuum reliability) and fabric-like characteristics (for user comfort). The stitch bonding process also modifies parameters by creating a coordinated web structure that further controls air flow while maintaining fabric properties
2Reliability
If an LDPE film substrate is used in the stitch-bonded loop face composite material, then air permeability is maintained at low levels for vacuum system reliability, but a fabric-like feel is not provided
Solution Approach 1:
The patent replaces the single LDPE film substrate with a composite of multiple nonwoven layers (spunbond and meltblown polypropylene). This composite structure maintains low air permeability through the meltblown layers while the spunbond layers and stitch bonding create fabric-like characteristics. This resolves the contradiction by using material composition rather than a single film type
Solution Approach 2:
The patent applies local quality by assigning different functions to different layers of the substrate. The meltblown layers locally provide liquid barrier and air permeability control, while the spunbond layers locally provide fabric-like feel and structural integrity. This localized functional distribution allows the substrate as a whole to achieve both low air permeability and fabric-like characteristics
3Reliability
If the substrate air permeability is reduced for reliable vacuum system operation, then vacuum system reliability improves, but the fabric-like feel deteriorates
Solution Approach 1:
The patent uses composite materials with different permeability characteristics in specific layer configurations. The meltblown layers provide low permeability for vacuum reliability, while the spunbond layers and stitch bonding pattern create fabric-like air flow characteristics that maintain user comfort. The composite structure allows simultaneous optimization of both parameters
Solution Approach 2:
The patent changes multiple parameters simultaneously including layer composition, weight distribution, and stitch bonding density to achieve the optimal balance. By coordinating these parameter changes, the substrate maintains low enough air permeability for vacuum reliability while preserving sufficient porosity and flexibility for fabric-like feel
Data Source
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AI summary
A composite loop face fabric which incorporates a multi-bar stitch-bonded construction and related fastening system. A yarn system forms an arrangement of surface loops extending in stitched relation through a composite nonwoven substrate incorporating one or more layers of melt blown nonwoven fibrous material in sandwiched relation to one or more layers of spunbond nonwoven fibrous material. Multiple layers of melt blown nonwoven material and/or spunbond nonwoven material may be used if desired.