Multi-Ply Flushable Wipe with Foam-Formed Core for Dispersibility
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Solution Overview
Problem
Current flushable wipe products are not truly flushable as they do not disperse well in household toilet/septic systems, often clogging sewage systems, and contain significant synthetic fibers, failing to meet eco-friendly and biodegradable standards.
Innovation Solution
A three-layer wipe with external layers made of 50-100% natural fibers and a core layer composed of a foam-formed fiber blend of natural and long synthetic fibers, using water-soluble binders with a trigger component that dissolves upon dilution to ensure the wipe disintegrates during flushing, preventing clogging and maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If size-based flushable wipes are used to pass through plumbing systems, then they can pass through immediately after flushing, but they do not break down into smaller pieces or fiber clusters and often plug up sewage systems and effluent clarifiers
Solution Approach 1:
The wipe is constructed with a multi-ply structure where outer plies contain short synthetic fibers (3-19mm) that segment easily during flushing, while the core ply provides structural support. This segmentation allows the wipe to break down into smaller pieces and fiber clusters that can pass through plumbing systems without clogging, while still maintaining sufficient integrity for immediate passage.
Solution Approach 2:
The patent changes the fiber length parameter of synthetic fibers to a specific range (3-19mm) that optimizes both dispersibility and pass-through speed. Additionally, the binder composition is adjusted to provide controlled strength that allows the wipe to maintain integrity during application and storage but disperse appropriately during flushing, resolving the contradiction between maintaining strength and enabling dispersal.
2Strength
If synthetic fibers are used in flushable wipes to maintain structural integrity, then the wipes can maintain strength properties, but they are not biodegradable and fail to meet eco-friendly standards
Solution Approach 1:
Different regions of the wipe have different fiber compositions optimized for their specific functions. The outer plies contain higher concentrations of short synthetic fibers (3-19mm) that provide localized strength where needed for handling and application, while the core ply uses predominantly natural fibers that will biodegrade in sewage systems. This local differentiation allows the wipe to maintain overall structural integrity while ensuring biodegradability in the disposal environment.
Solution Approach 2:
The wipe uses a composite material structure combining natural fibers (cellulose, wood pulp) with limited amounts of specific synthetic fibers (3-19mm length). The synthetic fibers are used only in outer plies at controlled concentrations to provide necessary strength properties for handling and pre-moistening, while the core ply relies on natural fibers that will biodegrade. This composite approach balances structural requirements with environmental concerns.
3Object-affected harmful factors
If natural fibers are used in external layers to improve biodegradability, then the wipes become more eco-friendly, but they may lose functional strength properties when pre-moistened
Solution Approach 1:
The wipe structure is pre-configured with outer plies containing short synthetic fibers (3-19mm) that provide strength reserves before the wipe is used. These fibers are positioned in the outer layers where they will provide mechanical strength during handling, application, and pre-moistening. The binder system is also pre-selected to maintain adequate wet strength while allowing dispersal in sewage systems, ensuring the wipe remains functional throughout its use cycle while maintaining eco-friendly 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 solution provides a truly flushable and biodegradable wipe that disintegrates in sewage systems, preventing clogging and ensuring eco-friendly disposal, while maintaining pre-moistened strength properties.
Implementation Method 1
using water-soluble binders with a trigger component that dissolves upon dilution to ensure the wipe disintegrates during flushing
Implementation Method 2
the wipe disintegrates when flushed and does not plug up city/municipal sewage systems
Data Source
AI summary
A multi-ply flushable wipe includes a ply having first and second exterior layers and a middle layer disposed therebetween. Each of the exterior layers includes at least 50% by weight natural fibers. When foam-formed, the middle layer includes at least 25% by weight natural fibers. In embodiments, the middle layer may include at least 75% by weight natural fibers. The middle layer also includes synthetic fibers that have a length within the range of 1 mm and 20 mm. The wipe may have a length weight weighted average fiber length of less than 4 mm and a wet CD strength of greater than 20 N/m. Each ply of the wipe may be formed by wetlaying the first and second exterior layers and a foam formed middle layer to form a web, imprinting the web with a structured fabric, and drying the web. The plies are then attached using a binder.