Co-Formed Fibrous Web Structure Balancing Wet Strength and Absorbency
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Solution Overview
Problem
Current wet wipes substrates face challenges in balancing mechanical strength, absorbency, and surface friction, with the inclusion of scrim layers affecting properties like tensile strength, drape, and consumer perception of surface roughness, while existing combinations of pulp and polymer fibers are not predictable in their effects on these properties.
Innovation Solution
A fibrous web structure with specific allocations of pulp fibers and meltblown polypropylene filaments between core and scrim layers, optimized to enhance tensile strength, opacity, and consumer preference, is developed, where the weight percent of pulp fibers ranges from 60% to 90% and meltblown polymer filaments from 10% to 40%, with a preferred allocation of meltblown filaments in scrim layers between 1% and 13% of the total structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If pulp fibers are used to improve absorbency and surface friction, then cleaning ability is enhanced, but structural integrity when wetted deteriorates
Solution Approach 1:
The patent uses a composite fibrous web structure combining cellulose pulp fibers with synthetic polymer fibers (polypropylene, polyester, or polyamide). The pulp fibers provide absorbency and surface friction for cleaning, while the synthetic polymer fibers maintain structural integrity when wetted, resolving the contradiction between cleaning ability and wet strength.
2Reliability
If synthetic polymer fibers are used to improve structural integrity when wetted, then wet strength is enhanced, but absorbency and surface friction deteriorate
Solution Approach 1:
The composite structure combines synthetic polymer fibers that provide wet strength with cellulose pulp fibers that provide absorbency and surface friction. This composite approach allows both properties to coexist, resolving the contradiction between wet strength and cleaning performance.
3Strength
If scrim layers are added to improve tensile strength and reduce lint release, then mechanical strength is enhanced, but surface friction and consumer perception of cleaning efficacy deteriorate
Solution Approach 1:
The patent applies local quality by concentrating the scrim layer (made of meltblown polymer filaments) specifically at the edges of the wipe rather than uniformly across the entire surface. This provides tensile strength and reduces lint release at critical stress points while preserving surface friction and cleaning perception in the user-contact areas.
4Strength
If more meltblown filaments are allocated to scrim layers to improve tensile strength, then mechanical strength is enhanced, but opacity and consumer preference deteriorate
Solution Approach 1:
The patent optimizes the parameter of meltblown filament allocation by limiting it to a narrow range of 1-13 weight percent in the scrim layer. This parameter optimization achieves sufficient tensile strength while maintaining adequate opacity and consumer preference, resolving the contradiction between mechanical strength and aesthetic/perceptual properties.
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 optimized fibrous web structure achieves improved tensile strength, opacity, and consumer preference, with a narrow band of meltblown filament allocation in scrim layers crucial for maximizing these properties, ensuring a balance that enhances both functional performance and consumer acceptance.
Implementation Method 1
a first scrim layer formed of meltblown filaments, the second scrim layer formed of meltblown filaments
Implementation Method 2
the layers being bonded together
Implementation Method 3
Due to their naturally greater hydrophilicity, and to the greater coefficient of friction and surface texture they impart, the pulp fibers impart desirable absorbency properties
Implementation Method 4
The moistened supply of wipes is typically packaged in a rigid dispensing tub or dispensing package of flexible film, designed to effectively retain the moisture in the lotion
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
An enhanced, co-formed fibrous web structure is disclosed. The web structure may have a co-formed core layer sandwiched between two scrim layers. The core layer may be formed of a blend of cellulose pulp fibers and melt spun filaments. The scrim layers may be formed of melt spun filaments. Filaments of one or both of the scrim layers, and optionally the core layer, may also be meltblown filaments. The core layer may include consolidated masses of cellulose pulp fibers to, for example, enhance texture and cleaning efficacy of a wet wipe made from the structure. The material forming the consolidated masses may be selected and/or processed so as to cause the masses to have reduced visual discernibility relative the surrounding areas of the structure, when the fibrous web structure is wetted. A method for forming the structure, including formation and inclusion of the consolidated masses, is also disclosed.