Waist Opening Texture in Pants-Type Disposable Diapers
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Solution Overview
Problem
Conventional underpants-type disposable diapers have an insufficient texture, particularly at the waist opening, due to inadequate softness and cushioning properties, which can lead to an uncomfortable experience when worn or handled.
Innovation Solution
The design incorporates a waist portion with elongated waist elastic members bonded to both sheet layers via hot melt adhesive, featuring a first portion where the elastic members are not fixed to an over sheet layer and a second portion where they are, allowing the over sheet layer to contract and form wrinkles, enhancing cushioning and softness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If all waist elastic members are fixed to both outer and inner sheet layers with hot melt adhesive, then structural stability is improved, but softness and cushioning property at the waist opening edge deteriorate
Solution Approach 1:
The patent divides the waist elastic member fixation into two segments: a first portion where elastic members are fixed to both outer and inner sheet layers with hot melt adhesive, and a second portion where elastic members are fixed to only one sheet layer. This segmentation allows the first portion to provide structural stability while the second portion maintains softness and cushioning property by reducing adhesive contact points.
Solution Approach 2:
The patent applies different fixation qualities to different portions of the waist elastic members. The first portion uses full fixation (both sheet layers) for stability, while the second portion uses partial fixation (one sheet layer) for softness. This local differentiation of fixation quality resolves the contradiction between structural stability and comfort.
2Object-affected harmful factors
If outer sheet layer and inner sheet layer are not bonded at the waist opening edge, then softness and cushioning property are improved, but structural integrity deteriorates
Solution Approach 1:
The patent segments the bonding region of the sheet layers into a first portion (closer to the waist opening) where outer and inner sheet layers are not bonded, and a second portion (farther from the waist opening) where they are bonded. This segmentation provides softness and cushioning at the waist opening edge while maintaining structural integrity through bonding in the second portion.
Solution Approach 2:
The patent applies different bonding qualities to different regions: the first portion has no bonding between sheet layers to maximize softness and cushioning, while the second portion has bonding to ensure structural integrity. This local differentiation resolves the contradiction between comfort and structural strength.
3Strength
If hot melt adhesive is applied planarly to bond sheet layers and fix elastic members, then bonding strength is improved, but softness deteriorates due to increased adhesive amount
Solution Approach 1:
The patent applies hot melt adhesive only partially to the waist elastic members - specifically to the first portion but not the second portion. This partial application maintains sufficient bonding strength where needed while reducing overall adhesive quantity to preserve softness in the second portion and at the waist opening edge.
Solution Approach 2:
The patent applies different adhesive quantities to different portions: the first portion receives full adhesive application for bonding strength, while the second portion receives no adhesive to maintain softness. This local differentiation of adhesive application resolves the contradiction between bonding strength and softness.
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
This configuration improves the texture of the waist opening by providing increased softness and cushioning, making the diaper feel softer when handled or worn, while maintaining a neat appearance.
Implementation Method 1
a waist inner sheet layer facing insides of the waist elastic members; and a waist outer sheet layer facing outsides of the waist elastic members, the waist elastic members being bonded to the waist inner sheet layer and the waist outer sheet layer via a hot melt adhesive
Implementation Method 2
in the second portion, the waist elastic member is fixed to the sheet material, and the sheet material is contracted in a width direction together with the waist elastic member
Data Source
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AI summary
To improve texture of an end portion of a waist opening. A waist portion W has a first portion P1 and a second portion P2 each including a waist elastic member 17. The first portion P1 includes an over sheet layer 127 folded back at an edge of a waist opening WO from an outside of a waist outer sheet layer 122 and extending to an inside of a waist inner sheet layer 121. The over sheet layer 127 is formed of a sheet material 12S having a portion folded back at an edge of the waist opening WO from a position outside the waist elastic member 17 in the second portion P2 and extending to a position inside the waist elastic member 17 in the second portion P2. In the first portion P1, the waist elastic member 17 is not fixed to the sheet material 12S. In the second portion P2, the waist elastic member 17 is fixed to the sheet material 12S, and the sheet material 12S is contracted in a width direction WD together with the waist elastic member 17.