Disposable Absorbent Core Immobilization via Patterned Deposition
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Solution Overview
Problem
Existing absorbent articles, such as diapers, face challenges in maintaining the immobilization of absorbent particulate polymer material in both dry and wet states while maintaining thinness, flexibility, and affordability, as current technologies either add bulk or fail to effectively immobilize the material when wet.
Innovation Solution
A method and apparatus for making disposable absorbent articles involve depositing absorbent particulate polymer material onto a substrate using a printing roll with a grid of cross bars, followed by applying a thermoplastic adhesive material to form an absorbent layer, ensuring the material remains immobilized in a pattern that maintains its position and absorbency across the article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If absorbent particulate polymer material is immobilized using existing technologies, then immobilization is improved, but article thickness increases and flexibility is reduced
Solution Approach 1:
The absorbent core is divided into multiple layers with different functions: a first layer with high immobilization capability and a second layer with high absorbency. This segmentation allows each layer to be optimized for its specific purpose, preventing the need for a single thick layer that would compromise flexibility.
Solution Approach 2:
Different regions of the absorbent core are given different properties: the first layer uses a lattice structure with immobilizing material for maximum immobilization, while the second layer uses fluff material for maximum absorbency. This local differentiation of properties achieves effective immobilization without uniformly increasing thickness throughout the entire core.
2Reliability
If absorbent particulate polymer material is immobilized using existing technologies, then immobilization is improved, but manufacturing cost increases
Solution Approach 1:
Instead of immobilizing all absorbent particulate polymer material throughout the entire core, the invention applies immobilizing material only in the first layer. This partial action is sufficient to prevent migration while reducing the total amount of expensive immobilizing material required, thereby lowering manufacturing costs.
Solution Approach 2:
The invention uses a composite structure combining different materials in different layers: a lattice structure with immobilizing material in the first layer, and fluff material in the second layer. This composite approach optimizes the use of materials by assigning each material to where it provides the most value, reducing overall material costs while maintaining performance.
3Reliability
If absorbent particulate polymer material is immobilized effectively in wet state, then immobilization is improved, but article flexibility is reduced
Solution Approach 1:
The absorbent core is segmented into two functional layers: the first layer provides wet immobilization through its lattice structure and immobilizing material, while the second layer maintains flexibility and softness through its fluff material composition. This segmentation allows the article to achieve both wet immobilization and flexibility simultaneously.
Solution Approach 2:
The use of a lattice structure in the first layer creates a flexible framework that can conform to the baby's body while still providing effective immobilization. The open lattice structure allows the layer to remain flexible rather than rigid, maintaining article flexibility while achieving wet immobilization.
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 approach results in a thin, flexible, and cost-effective absorbent article with enhanced immobilization of absorbent particulate polymer material in both dry and wet states, improving comfort and performance by maintaining the material's position and absorbency effectively.
Implementation Method 1
depositing absorbent particulate polymer material from a plurality of reservoirs in a printing roll onto a substrate
Implementation Method 2
applying a thermoplastic adhesive material to form an absorbent layer, ensuring the material remains immobilized
Data Source
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AI summary
A method for making a disposable absorbent core comprises depositing absorbent particulate polymer material from a plurality of reservoirs in a printing roll onto a substrate disposed on a grid of a support which includes a plurality of cross bars extending substantially parallel to and spaced from one another so as to form channels extending between the plurality of cross bars. The plurality of reservoirs in the first peripheral surface are arranged in an array comprising rows extending substantially parallel to and spaced from one another. The support and printing roll are arranged such that the plurality of cross bars are substantially parallel to the rows of the plurality of reservoirs and the absorbent particulate polymer material is deposited on the substrate in a pattern such that the absorbent particulate polymer material collects in rows on the first substrate formed between the first plurality of cross bars. A thermoplastic adhesive material is deposited on the absorbent particulate polymer material and the substrate to cover the absorbent particulate polymer material on the substrate and form an absorbent layer. A disposable absorbent article and apparatus for making an absorbent article are also disclosed.