Elastic Sheet Structure to Reduce Skin Gather Marks
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Solution Overview
Problem
Conventional elastic sheets for absorbent articles often leave gather marks on the wearer's skin due to their rigidity and adhesive properties, compromising fitability and comfort.
Innovation Solution
An elastic sheet design featuring a first fibrous layer with low rigidity and high flexibility, constructed of spun-melt nonwoven fabrics with polyethylene fibers, and a second fibrous layer with higher rigidity and polypropylene fibers, both with specific flexural rigidity values and thickness under compression, to minimize gather marks by dispersing contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pitch of elastic members is increased to suppress bite into wearer's skin, then gather marks are reduced, but fittability to wearer's skin is degraded
Solution Approach 1:
The patent applies different properties to different regions by using a dual-layer fibrous nonwoven fabric structure where the first layer (skin-facing) has lower rigidity to reduce gather marks, while the second layer maintains sufficient rigidity for structural support and fitability. This local differentiation allows the skin-contact surface to be soft and compliant while the overall structure retains elasticity and fit.
Solution Approach 2:
The patent uses a composite structure combining two types of fibrous nonwoven fabrics with different rigidity characteristics. The first fibrous nonwoven fabric (skin-facing) has flexural rigidity of 0.003 to 0.020×10^-4 N·m^2/m, while the second layer has higher rigidity. This composite material approach allows simultaneous achievement of skin comfort (reduced gather marks) and functional performance (fittability).
2Ease of operation
If adhesive amount is decreased to reduce rigidity of fibrous nonwoven fabric, then flexibility is improved, but elastic members may be released from the sheet
Solution Approach 1:
The patent applies adhesive selectively in specific regions rather than uniformly across the entire sheet. Adhesive is applied to the peripheral portions of the elastic members to provide secure anchoring, while the central regions maintain lower adhesive content to preserve flexibility and comfort. This localized adhesive application resolves the contradiction between securing reliability and flexibility.
Solution Approach 2:
The patent introduces a specifically designed adhesive as an intermediary substance that bonds elastic members to the fibrous nonwoven fabric. This adhesive mediator provides sufficient bonding strength to prevent release of elastic members while maintaining overall sheet flexibility through controlled application amount and distribution pattern.
Data Source
AI summary
An elastic sheet for an absorbent article includes a first fibrous layer disposed on a first surface of the elastic sheet, a second fibrous layer disposed on a second surface of the elastic sheet opposite to the first surface, and contractible elastic members secured between the first fibrous layer and the second fibrous layer. The first fibrous layer and the second fibrous layer each include continuous fibers of thermoplastic and gathers formed between adjacent ones of the elastic members. The gathers are disposed in an intersecting direction intersecting with a direction in which the elastic members extend. An average flexural rigidity value of the first fibrous layer and the second fibrous layer in accordance with a KES method is 0.0035×10−4 to 0.022×10−4 (N·m2/m). A thickness under a compression load to the gathers in accordance with the KES method is 0.22 to 1.5 mm.