Composite Sheet Breathability via Curved Layer Joints
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Solution Overview
Problem
Conventional composite sheets used in disposable wearing articles suffer from reduced breathability due to the elastic sheet flattening against the skin, and existing manufacturing methods do not adequately address the need for high breathability.
Innovation Solution
A composite sheet design featuring an elastic layer and an inelastic layer joined at spaced joints, with the elastic layer having first protrusions and depressions in the transverse direction and the inelastic layer having second protrusions and depressions in the longitudinal direction, ensuring high breathability by creating clearance gaps and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the elastic sheet is flattened and bonded to the inelastic sheet, then the composite sheet structure is simplified and manufacturing is easier, but the breathability deteriorates because the flattened surface clings to the skin
Solution Approach 1:
The elastic sheet is designed with a curved surface having a specific radius of curvature (R1) that matches or is larger than the curvature of the human body part it contacts. This curvature prevents the sheet from flattening completely against the skin, maintaining air gaps that ensure breathability while still providing conformal contact for comfort and fit.
Solution Approach 2:
The invention transitions from a two-dimensional flattened surface to a three-dimensional curved surface. By introducing curvature as an additional spatial dimension, the elastic sheet maintains contact with the skin's contours while preserving air circulation spaces, thereby resolving the contradiction between fit and breathability.
2Adaptability or versatility
If the elastic sheet is made highly stretchable to conform to body contours, then comfort and fit are improved, but the sheet may cling too closely to the skin reducing breathability
Solution Approach 1:
The elastic sheet's curved surface geometry allows it to conform to body contours through its inherent shape rather than excessive stretching. The radius of curvature is designed to match body proportions, enabling the sheet to adapt to different body parts while maintaining air gaps that preserve breathability.
Solution Approach 2:
The invention optimizes the radius of curvature parameter (R1) of the elastic sheet to achieve the desired balance. By carefully selecting this geometric parameter to be equal to or larger than the body part's curvature radius, the sheet achieves conformability without over-stretching, thus maintaining breathability.
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 design enhances breathability and flexibility, preventing the composite sheet from clinging to the skin and maintaining desired clearance gaps, thereby improving comfort and preventing skin issues.
Implementation Method 1
a method for manufacturing the composite sheet including a step of joining a nonwoven fabric layer as the inelastic sheet to an elastic base layer as the elastic sheet with use of an ultrasonic system including an anvil and a horn
Data Source
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AI summary
The present invention aims to provide a composite sheet having an elastic layer and an inelastic layer so improved to ensure high breathability and a method for manufacturing such improved composite sheet. A composite sheet (1) includes an elastic layer (11) and an inelastic layer (12) joined and laminated through a plurality of joints (13). The elastic layer (11) is formed with first depressions (14) overlapping the joints (13) and extending in a transverse direction X and first protrusions (15). Interior space if the first protrusions (15) is filled with constituent fibers of the elastic layer (11). The inelastic layer (12) is formed with second depressions (16) overlapping the joints (13) and extending in a longitudinal direction Y and second protrusions (17). Along the second depressions (16), the elastic layer (11) and the inelastic layer (12) come in contact with each other at the joints (13) and, along the second protrusions (17), the inelastic layer (12) is spaced from the elastic layer (11) to define clearance gaps (18) these layers. {Description}