Absorbent Article Bonding Layer for Tearing Prevention
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Solution Overview
Problem
Low-cost soft and silky tactile topsheet materials with weak cross-directional strength in absorbent articles tend to detach or tear during use due to inadequate bonding methods, which compromise the integrity and comfort of the product.
Innovation Solution
A bonding layer comprising a fibrous matrix of cellulosic and thermoplastic fibers is used to directly bond the topsheet to the absorbent core without adhesives, providing improved strength and comfort by dissipating bonding forces and preventing bond destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If typical bonding methods such as fusion bonding are used to bond low-cost soft and silky topsheet materials to an absorbent layer, then bonding between the layers is achieved, but the material strength is compromised and the topsheet may detach or tear during use
Solution Approach 1:
A bonding layer comprising a fibrous matrix of cellulosic and thermoplastic fibers is introduced as an intermediary between the topsheet and absorbent core. This bonding layer distributes bonding forces across multiple fibers rather than concentrating stress at single bond points, preventing topsheet tearing while achieving reliable bonding. The bonding layer acts as a stress-distributing mediator that protects the weak topsheet material.
Solution Approach 2:
The bonding layer is formed as a composite material combining cellulosic fibers (providing softness and compatibility with topsheet) and thermoplastic fibers (providing bonding capability through heat activation). This composite structure enables the bonding layer to simultaneously provide gentle bonding forces and mechanical strength distribution, resolving the contradiction between bonding strength and topsheet integrity.
2Strength
If adhesive is applied to bond sites to strengthen bonding between topsheet and absorbent layer, then bonding strength is improved, but the article becomes stiffer and less comfortable
Solution Approach 1:
The invention replaces the chemical bonding mechanism of adhesives with a mechanical/thermal bonding mechanism using thermoplastic fibers. The thermoplastic fibers are activated through heat and pressure to create mechanical interlocking with the topsheet and absorbent core, eliminating the need for adhesives. This substitution maintains bonding strength while preserving the soft, comfortable feel of the article.
Solution Approach 2:
The bonding properties of the thermoplastic fibers are changed through parameter modification during processing. By controlling temperature, pressure, and fiber composition, the thermoplastic fibers transition from a bonded state during manufacturing to a flexible, comfort-providing state during use. This parameter control enables strong bonding without permanent stiffness.
3Ease of manufacture
If low-cost topsheet materials are used to reduce manufacturing cost, then cost is reduced, but the material has weak cross-directional strength and is prone to tearing
Solution Approach 1:
The bonding function is segmented from the topsheet material itself and transferred to a separate bonding layer. This allows the topsheet to be made from low-cost materials optimized for comfort and cost, while the bonding layer provides the necessary mechanical strength and bonding capability. The segmentation of functions enables cost reduction without sacrificing performance.
Solution Approach 2:
The bonding layer serves as an intermediary that compensates for the weak cross-directional strength of low-cost topsheet materials. By distributing stresses across the fibrous matrix of the bonding layer rather than relying on the weak topsheet material alone, the system enables use of economical topsheet materials without compromising durability.
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 enhances the bonding between the topsheet and absorbent core, preventing tearing and maintaining comfort by avoiding stiffness increases, thus improving the durability and usability of absorbent articles like sanitary napkins and pantiliners.
Implementation Method 1
a bonding layer having a body facing surface and a garment facing surface. The body facing surface of the bonding layer has a fibrous matrix comprising cellulosic fibers and thermoplastic fibers
Data Source
AI summary
An absorbent article is provided. The absorbent article includes a liquid pervious film topsheet having a body facing surface and a garment facing surface; a backsheet having a body facing surface and a garment facing surface; an absorbent core having a body facing surface and a garment facing surface, the absorbent core being provided between the topsheet and the backsheet; and a bonding layer having a body facing surface and a garment facing surface. The body facing surface of the bonding layer has a fibrous matrix comprising cellulosic fibers and thermoplastic fibers, and the garment facing surface of the topsheet is directly bonded to the body facing surface of the bonding layer at discrete adhesive-free bond points.