Durable and dispersible creped multi-ply tissue
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Solution Overview
Problem
There is a need for single-use tissue products that maintain dry durability while ensuring rapid breakup in aqueous environments to prevent clogging of domestic waste disposal or septic systems, as existing technologies often compromise on either dry strength or wet dispersability.
Innovation Solution
Creped tissue webs with multiple plies, where each ply has a non-crosslinked latex binder on its surface, providing high dry durability and rapid wet dispersability, achieving Slosh times less than 2 minutes and high cross-machine direction wet tensile strength without negatively affecting dispersability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water soluble fibers or water sensitive binders are used to enable rapid dispersability, then wet dispersability is improved, but dry durability deteriorates
Solution Approach 1:
The patent uses a non-crosslinked latex binder that changes its properties based on environmental conditions: it maintains integrity in dry states for durability but disperses rapidly when wetted. This parameter change approach allows the same material to satisfy both contradictory requirements under different conditions.
Solution Approach 2:
The invention combines conventional wood pulp fibers with a non-crosslinked latex binder to create a composite fibrous structure. The latex binder provides the composite nature that enables both dry strength and wet dispersability, as it binds fibers together in dry state but breaks down in aqueous environments.
2Strength
If wet tensile strength is increased to improve dry durability, then dry strength is improved, but dispersability deteriorates and Slosh time increases
Solution Approach 1:
The non-crosslinked latex binder exhibits parameter changes based on moisture content: it provides sufficient binding strength in dry conditions for durability but loses this strength and disperses when exposed to water, thus resolving the contradiction between dry strength and wet dispersability.
3Strength
If crosslinked latex binder is used to enhance durability, then dry and wet strength are improved, but dispersability is negatively affected
Solution Approach 1:
The patent extracts the crosslinking component from the latex binder system, using only non-crosslinked latex. This extraction removes the permanent bonding capability that would prevent dispersal, while retaining the temporary binding ability needed for durability during use.
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 creped multi-ply tissue products exhibit improved dry durability and rapid wet breakup, achieving Slosh times less than 2 minutes and high cross-machine direction wet tensile strength, maintaining product flexibility and dispersability.
Implementation Method 1
a non-crosslinked binder disposed on the first or the second surface
Implementation Method 2
two or more creped tissue plies
Data Source
AI summary
Disclosed are multi-ply tissue products comprising a non-crosslinked binder that are durable and dispersible. The products generally have a Slosh time less than 2 minutes, such as less than about 60 seconds, such as less than about 45 seconds. Surprisingly, the foregoing Slosh times are achieved despite the tissue products having relatively high cross-machine direction (CD) wet tensile strength, such as greater than about 100 g/3″. Typically, increasing wet tensile strength, particularly wet CD tensile strength, negatively effects dispersability and increases Slosh time. Despite this trend, the present invention surprisingly provides a tissue product having a relatively high degree of wet strength and good dispersability.