Water-Disintegrable Sheet with Gradient Binder for Tear Resistance
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Solution Overview
Problem
Conventional water-disintegrable sheets used for toilet cleaning often tear when used for strong rubbing, compromising their tear resistance while maintaining water-disintegrability.
Innovation Solution
A water-disintegrable sheet with a base paper weight of 30 to 150 gsm, impregnated with a water-soluble binder and cellulose nanofibers, and an aqueous agent containing a cross-linking agent, where the binder content increases from the inner to the outer surface, enhancing wet tensile strength and tear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional water-disintegrable sheet is used for strong rubbing, then the sheet can clean the toilet surface, but the sheet tears and loses its structural integrity
Solution Approach 1:
The patent applies different binder concentrations at different locations within the sheet structure. The water-soluble binder content gradually increases from the inner side toward the front and back surfaces, creating local variations in strength and disintegration properties. This allows the surface layers to provide tear resistance during rubbing while the inner layers maintain water-disintegrability for safe flushing.
Solution Approach 2:
The patent uses a composite structure combining base paper with water-soluble binder and cellulose nanofibers. This composite material system provides both mechanical strength for rubbing operations and controlled water-disintegrability for safe disposal, resolving the contradiction between durability and environmental safety.
2Strength
If the binder content is increased throughout the sheet to improve tear resistance, then the sheet becomes stronger, but the water-disintegrability is compromised
Solution Approach 1:
Instead of uniformly distributing the binder throughout the sheet, the patent creates a gradient distribution where binder content varies by location. The surfaces have higher binder concentration for strength, while the interior maintains lower concentration for disintegrability, thus resolving the contradiction between wet tensile strength and water-disintegrability.
Solution Approach 2:
The patent changes the concentration parameter of the water-soluble binder spatially within the sheet structure. By controlling the binder content to gradually increase from inner to outer surfaces, the patent optimizes both strength and disintegration properties without compromising either characteristic.
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 sheet exhibits improved tear resistance against strong rubbing while maintaining water-disintegrability, enhancing its wiping properties and durability.
Implementation Method 1
the aqueous agent includes a cross-linking agent which cross-links with a water-soluble binder
Implementation Method 2
the surface strength of the base paper sheet can be improved. Further, by impregnating the base paper sheet with an aqueous agent containing a cross-linking agent which cross-links with the water-soluble binder, the added cellulose nanofibers can improve the wet tensile strength
Data Source
AI summary
A water-disintegrable sheet in which a base paper sheet is impregnated with an aqueous agent is provided. The base paper sheet has a weight per unit area of 30 to 150 gsm, and includes a water-soluble binder and cellulose nanofibers. The aqueous agent includes a cross-linking agent which cross-links with a water-soluble binder.