Multistrata Nonwoven Wipe Structure for Flushability and Wet Strength
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Solution Overview
Problem
Current disposable wipes often lack the necessary strength for effective use while being flushable and dispersible in conventional toilets and wastewater systems, leading to potential blockages and stress on the wastewater conveyance and treatment systems. Existing solutions, such as using water-soluble binders or triggers, are ineffective in varying water conditions like hard water, and materials like polyvinyl alcohol become unstable in humid environments.
Innovation Solution
A multistrata nonwoven wipe material composed of cellulosic and bicomponent fibers, with specific layer compositions and binder applications, that maintains strength in wet conditions and disperses easily through wastewater systems, passing industry flushability tests like the INDA Guidelines FG 512.1 Column Settling Test and FG 521.1 30 Day Laboratory Household Pump Test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the size of the wipe product is limited to pass through plumbing, then flushability is improved, but the product loses in-use strength and fails to disintegrate properly
Solution Approach 1:
The wipe is constructed with multiple layers having different fiber compositions and bonding characteristics. The outer layers provide strength for effective cleaning, while the inner layers are designed to disintegrate more readily in wastewater systems, enabling both flushability and adequate in-use strength
Solution Approach 2:
The patent uses water-soluble binders with controlled solubility parameters that allow the wipe to maintain integrity during use but dissolve at specific rates in wastewater. By adjusting binder composition and concentration, the wipe achieves optimal balance between strength and dispersibility
2Ease of operation
If water-soluble binders are used to enable dispersibility, then flushability is improved, but the binders dissolve in humid environments causing instability
Solution Approach 1:
The binder is applied in controlled amounts during manufacturing with preliminary protection measures. The wipe structure is designed to maintain binder stability during storage and converting processes, then trigger controlled dissolution in wastewater through water activation mechanisms
Solution Approach 2:
The patent combines water-soluble binders with hydrophobic fibers and coating materials to create a composite structure. This composite approach allows the binder to provide necessary adhesion and controlled dispersibility while the hydrophobic components protect against premature dissolution in humid storage conditions
3Ease of operation
If polyvinyl alcohol is used as a binder for flushability, then dispersibility is improved, but the material becomes unstable in humid storage conditions
Solution Approach 1:
The patent introduces intermediate protective layers or coatings that act as barriers between the polyvinyl alcohol binder and humid storage environments. These intermediates prevent premature water absorption while allowing controlled water penetration during flushing
Solution Approach 2:
The polyvinyl alcohol binder is modified with cross-linking agents or blended with other polymers to adjust its water sensitivity parameters. This modification reduces hygroscopicity for storage stability while maintaining water-solubility for flushability
4Strength
If non-dispersible wipes are used to maintain strength, then in-use strength is improved, but blockages occur in wastewater systems
Solution Approach 1:
The wipe is divided into functional zones with different dispersibility characteristics. High-strength outer layers provide cleaning effectiveness, while inner layers are designed to break down into small particles that can pass through wastewater treatment systems without causing blockages
Solution Approach 2:
The patent designs the wipe to selectively discard certain components (water-soluble binders, inner layers) in the wastewater system while retaining essential cleaning components. The discarded portions disintegrate to prevent blockages, while the retained portions maintain cleaning effectiveness
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 material achieves high dry and wet strength, ensuring effective use while easily dispersing through wastewater systems, reducing the risk of blockages and maintaining performance across different water conditions.
Implementation Method 1
incorporation of water-soluble or redispersible polymeric binders
Implementation Method 2
incorporation of biodegradable polymers
Data Source
AI summary
A dispersible, nonwoven multistrata wipe material is provided that is stable in a wetting liquid and flushable in use. More particularly, multilayered structures including, but not limited to, two, three, or four layers are provided to form the dispersible nonwoven wipe material. The layers contain combinations of cellulosic and noncellulosic fibers, and optionally a binder or additive.