Co-Formed Fibrous Web Structure for Wet Strength and Opacity
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Solution Overview
Problem
The co-forming process for producing wet wipes lacks predictability in the properties such as tensile strength, drape, surface friction, opacity, texture, and feel due to unclear proportions of components in scrim layers and core layers, affecting the overall performance of the fibrous web structure as a wet wipe substrate.
Innovation Solution
The fibrous web structure is optimized by determining the appropriate allocation of meltblown polypropylene filaments between the core and scrim layers, with a predictive model indicating that reallocating filaments from the core to the scrim layers enhances wet tensile strength and opacity, while maintaining consumer preference for flexibility and surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If meltblown polypropylene filaments are allocated primarily to the core layer, then the structure provides basic structural support, but wet tensile strength and opacity are insufficient
Solution Approach 1:
The patent applies local quality by differentiating the functional requirements of different layers: the scrim layers are optimized for tensile strength and opacity with higher filament content (3-15 gsm per layer), while the core layer focuses on absorbency and softness with primarily cellulose fibers. This localized optimization resolves the contradiction by allocating filaments to specific locations where they provide maximum benefit rather than uniformly distributing them.
Solution Approach 2:
The patent employs parameter changes by establishing specific quantitative ranges for filament allocation: scrim layers contain 3-15 gsm of meltblown polypropylene filaments per layer, while the core layer contains 0-5 gsm. These defined parameters transform the unpredictable component allocation into a controlled, predictable manufacturing process that consistently achieves the desired wet tensile strength and opacity.
2Strength
If more meltblown filaments are added to the fibrous web structure, then wet tensile strength increases, but material cost and environmental sustainability are adversely affected
Solution Approach 1:
The patent applies partial action by adding meltblown filaments only to the extent necessary to achieve the desired wet tensile strength (3-15 gsm per scrim layer), rather than using excessive amounts. This partial allocation to specific layers provides the minimum necessary polymer content to achieve the strength target while minimizing material usage and cost.
Solution Approach 2:
The patent uses composite materials by combining cellulose fibers with meltblown polypropylene filaments in a multi-layer structure. The composite structure leverages the hydrophilic properties of cellulose for absorbency and the hydrophobic, high-strength filaments for tensile strength, achieving optimal performance with reduced total material content compared to using either material alone.
3Ease of operation
If the fibrous web structure is made softer to improve tactile sensation, then user comfort increases, but structural integrity when wetted is compromised
Solution Approach 1:
The patent applies local quality by creating distinct layers with different properties: the core layer uses soft, absorbent cellulose fibers for tactile comfort, while the scrim layers use stronger meltblown filaments for structural integrity when wet. This localized differentiation allows the structure to simultaneously achieve softness where needed and strength where required.
Solution Approach 2:
The patent uses composite materials to combine the soft, hydrophilic cellulose fibers with the stronger, hydrophobic meltblown polypropylene filaments. The composite structure allows the cellulose core to provide softness and absorbency while the filament scrim layers provide the tensile strength needed to maintain structural integrity when wetted, resolving the contradiction between softness and wet strength.
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 allocation of filaments in the fibrous web structure significantly increases wet tensile strength and opacity, aligning with consumer preferences for a balanced performance in wet wipes, including strength, flexibility, and tactile feel.
Implementation Method 1
The fibrous web structure is optimized by determining the appropriate allocation of meltblown polypropylene filaments between the core and scrim layers
Implementation Method 2
a predictive model indicating that reallocating filaments from the core to the scrim layers enhances wet tensile strength and opacity
Data Source
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 fibrous web structure may have a Consumer Preference Indication (governing allocation of melt spun filaments between core layer and scrim layers) greater than 0. Alternatively, the filaments forming the scrim layers may constitute from 1 to 13 percent of the weight of the structure. Alternatively, the scrim layers may have a combined basis weight of from 0.1 gsm to less than 3.0 gsm. A method for forming the structure, including direct formation of layers, is also disclosed.