Multi-Ply Dispersible Nonwoven for Wet Strength and Flushability
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Solution Overview
Problem
Existing flushable wet wipes face challenges in achieving sufficient wet strength without using binders or oil-based synthetic fibers, which can lead to clogging and slow dispersion, and are often costly.
Innovation Solution
A nonwoven material composed of at least two hydroentangled webs, each containing 50%-95% wood pulp and 5%-50% short cut man-made or natural fibers, joined by thermal or mechanical embossing, providing higher collective wet strength while ensuring rapid dispersion after flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wet strength agents or water soluble adhesives are added to pre-moistened wipes, then sufficient wet strength is achieved, but dispersibility becomes insufficient and blockage risks increase
Solution Approach 1:
The nonwoven material is divided into multiple plies (at least two) that are mechanically bonded together without using wet strength agents or adhesives. Each ply maintains its structural integrity while the mechanical bonding provides sufficient wet strength, and the segmentation allows rapid dispersibility when flushed, as each ply can separate and disperse independently.
Solution Approach 2:
The invention extracts and eliminates the use of wet strength agents, water soluble adhesives, and triggerable binders from the nonwoven material composition. By removing these binding agents, the material achieves dispersibility without sacrificing wet strength, as the mechanical bonding structure provides the necessary strength without chemical binders that would hinder dispersal.
2Reliability
If short fibers are used to provide good dispersability, then dispersibility improves, but surface and feel characteristics deteriorate
Solution Approach 1:
The nonwoven material uses a heterogeneous fiber composition where different fiber types and lengths are distributed throughout the structure. This local quality variation allows short fibers to provide dispersibility in specific regions while longer fibers or different fiber types maintain surface characteristics and feel in other regions, achieving both dispersability and comfort.
3Ease of operation
If long fibers are used to provide desired surface and feel characteristics, then surface quality improves, but dispersibility worsens due to accumulation on sewer screens
Solution Approach 1:
The material is structured as multiple plies that can separate during flushing, and the fiber composition includes a mix of fiber lengths that are mechanically bonded rather than chemically bound. This segmentation allows long fibers to provide surface quality while the mechanical bonding structure enables the plies to separate and disperse, preventing long fibers from accumulating on sewer screens.
4Strength
If binders are used to join nonwoven webs, then structural integrity improves, but dispersibility and flushability deteriorate
Solution Approach 1:
The invention completely eliminates the use of binders, adhesives, or chemical bonding agents to join the nonwoven webs. Instead, mechanical bonding methods are employed to provide structural integrity while maintaining the ability of the material to disperse and flush without chemical residues that would hinder dispersibility.
Solution Approach 2:
The invention replaces chemical bonding systems (binders and adhesives) with mechanical bonding systems. The nonwoven webs are joined through mechanical interlocking structures that provide sufficient structural integrity for use and dispensing, but allow the material to separate and disperse when subjected to flushing conditions, achieving both strength and flushability.
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 in-use strength and rapid dispersibility, meeting flushability standards with 50-100% pass-through in 5 minutes, without using binders or synthetic fibers, thus preventing clogging and reducing costs.
Implementation Method 1
The nonwoven webs are joined together by thermal or mechanical embossing
Implementation Method 2
The nonwoven webs are joined together by thermal or mechanical embossing
Data Source
AI summary
The invention relates to a nonwoven material having sufficient strength to be used in a pre-moistened state but also having dispersibility properties which allow the product to be flushed. The material comprises at least two nonwoven webs, at least one of which is hydroentangled. Each of the individual webs has a basis weight of 20-100 gsm. The nonwoven webs are joined together by thermal or mechanical embossing, or a combination of these.