Nonwoven Core Wrap for Softness and Rapid Wetness Detection
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Solution Overview
Problem
Existing absorbent articles face challenges in achieving improved softness without compromising the quick reaction time of wetness indicators, while also maintaining low manufacturing costs.
Innovation Solution
A nonwoven web structure comprising a first and second spunbond layer with a meltblown layer in between, optimized with a total basis weight of at least 10 gsm and a pore size distribution where greater than 80% of pores are 40 μm or smaller, and less than 10% are 45 μm or larger, is used as a core wrap in absorbent articles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the basis weight of soft nonwoven is increased to improve softness, then softness is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by creating a multilayer nonwoven structure where different layers serve different functions: the meltblown layer (third layer) provides softness and masks graininess, while the spunbond layers (first and second layers) provide structural support and containment. This localized functional distribution allows achieving softness without uniformly increasing basis weight across the entire nonwoven, thereby controlling manufacturing costs.
Solution Approach 2:
The patent uses composite materials by combining three different nonwoven layers (two spunbond layers and one meltblown layer) into a integrated core wrap structure. The meltblown layer with basis weight ≤4 gsm and specific pore size distribution (≤80% of pores ≤40 μm) provides the softness function, while the spunbond layers provide containment. This composite approach achieves the desired softness performance without requiring excessive material quantity.
2Quantity of substance
If SAP percentage is increased to improve absorbency, then absorbency is improved, but graininess increases
Solution Approach 1:
The patent applies local quality by positioning the meltblown layer specifically at the garment-facing side of the absorbent core, where it directly contacts the wearer's skin. This layer with its fine fiber structure and controlled pore size (≤80% of pores ≤40 μm) locally masks the graininess caused by high SAP content in the absorbent core, allowing high SAP percentage to be used without compromising comfort.
Solution Approach 2:
The meltblown layer acts as an intermediary between the SAP-containing absorbent core and the wearer's skin. It mediates the interaction by providing a soft, graininess-free surface that masks the underlying SAP particles, thereby allowing high SAP content to be utilized while maintaining comfort.
3Object-affected harmful factors
If nonwoven basis weight is increased to mask graininess, then softness is improved, but wetness indicator reaction time is delayed
Solution Approach 1:
The patent applies local quality by restricting the meltblown layer's basis weight to ≤4 gsm and limiting its thickness, while maintaining a specific pore size distribution (≤80% of pores ≤40 μm). This localized optimization provides sufficient softness and graininess masking at the skin interface without creating a thick barrier that would delay wetness indicator reaction.
Solution Approach 2:
The patent utilizes porous materials by specifying that ≤80% of pores in the nonwoven have size ≤40 μm and <10% have size ≥45 μm. This controlled porosity allows rapid fluid penetration to the wetness indicator while the meltblown fibers mask graininess, resolving the contradiction between softness and reaction time.
4Productivity
If pore size is increased to improve fluid flow, then fluid flow is improved, but SAP leakage increases
Solution Approach 1:
The patent applies porous materials principle by precisely controlling the pore size distribution of the nonwoven core wrap, specifying that ≤80% of pores have size ≤40 μm and <10% have size ≥45 μm. This controlled porosity allows sufficient fluid flow for wetness indicator function while the fine pore structure prevents SAP particle leakage through the core wrap.
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 softness of absorbent articles by masking the grainy feel of superabsorbent polymers while ensuring a rapid color change of the wetness indicator, thus providing an early warning of wetness events.
Implementation Method 1
greater than about 80% of the pores has a pore size equal to or smaller than about 40 μm, and less than about 10% of the pores has a pore size equal to or greater than about 45 μm
Data Source
AI summary
A nonwoven web for an absorbent article is provided. The absorbent article comprises the nonwoven web as a core wrap. A method for producing the absorbent article is also provided. The nonwoven web comprises a first nonwoven layer comprising filament fibers, a second nonwoven layer comprising filaments fibers, a third nonwoven layer comprising staple fibers disposed between the first and second nonwoven layers. A total basis weight of the first and second nonwoven layers is not less than about 10 gsm. The third nonwoven layer has a basis weight no greater than about 4 gsm. The nonwoven web comprises pores, wherein greater than about 80% of the pores have a pore size equal to or smaller than about 40 μm, and wherein less than about 10% of the pores have a pore size equal to or greater than about 45 μm.