Water-disintegrable sheet

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Solution Overview

Problem

Conventional wet sheets used for toilet cleaning often tear during vigorous rubbing and lack sufficient sterilizing effectiveness, while also potentially clogging toilets due to inadequate hydrolyzability.

Innovation Solution

A multi-ply hydrolysable sheet with a water-dispersible base paper containing pulp and a water-soluble binder, impregnated with an aqueous chemical agent, featuring embossments on its surface to enhance tearing resistance and sterilizing properties, with a compounding ratio of softwood to hardwood pulp less than 1:1 and a chemical solution including cross-linking and sterilizing agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional wet sheet is used for toilet cleaning, then it can be disposed of by flushing, but it tears during vigorous rubbing and may clog pipes

Engineering Contradiction:
Improvetearing resistanceVSAvoidhydrolyzability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating embossed portions with different physical properties from the non-embossed portions. The embossed areas have increased water permeability and altered surface characteristics, allowing the sheet to maintain strength where needed while facilitating disintegration in specific regions during flushing, thus resolving the contradiction between tearing resistance and hydrolyzability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sheet is segmented into embossed and non-embossed portions, creating distinct functional zones. The embossed portions are designed to disintegrate more readily during flushing, while the non-embossed portions maintain structural integrity during use, effectively segmenting the functions of strength and disposability within a single sheet

Inventive Principle:
Principle #1Segmentation

2Reliability

If the sheet is made thinner to improve hydrolyzability, then it flushes better, but it becomes weaker and tears more easily

Engineering Contradiction:
ImprovehydrolyzabilityVSAvoidtearing resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Rather than uniformly thinning the entire sheet, the patent applies local quality by creating embossed portions with modified thickness and density characteristics. These embossed areas are strategically designed to be more susceptible to water penetration and disintegration, while maintaining overall sheet strength through the non-embossed regions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sheet functions as a composite structure with embossed and non-embossed portions having different physical properties. This composite approach allows the sheet to exhibit both high strength (from non-embossed areas) and high hydrolyzability (from embossed areas) simultaneously, resolving the contradiction between thickness-related strength and disposability

Inventive Principle:
Principle #40Composite materials

3Strength

If a water-soluble binder is added to enhance strength, then tearing resistance improves, but hydrolyzability decreases and the sheet may not flush properly

Engineering Contradiction:
Improvetearing resistanceVSAvoidhydrolyzability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by concentrating the water-soluble binder in the embossed portions rather than distributing it uniformly throughout the sheet. This localized concentration allows the embossed areas to maintain strength during use while being designed to disintegrate during flushing, whereas the non-embossed portions with lower binder content maintain hydrolyzability for proper disposal

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of binder distribution from uniform to non-uniform, with varying concentrations in different portions of the sheet. This parameter change allows optimization of both strength (higher binder in embossed areas) and hydrolyzability (lower binder in non-embossed areas), resolving the contradiction between these two properties

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the sheet is impregnated with a higher concentration of cleaning agent to enhance sterilizing effect, then sterilizing performance improves, but the sheet becomes stiffer and more prone to tearing

Engineering Contradiction:
Improvesterilizing effectVSAvoidtearing resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by concentrating the cleaning agent and cross-linking agent in the embossed portions where sterilizing effect is most needed. This localized high-concentration impregnation provides enhanced sterilizing performance in critical areas while the non-embossed portions maintain flexibility and strength, resolving the contradiction between sterilizing effect and tearing resistance

Inventive Principle:
Principle #3Local quality

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 provides enhanced resistance to tearing and improved sterilizing effects while ensuring hydrolyzability, allowing it to be effectively used for vigorous cleaning without clogging toilets.

Implementation Method 1

a water-soluble binder... hydrolyzability is required so as not to clog a pipe or the like when being flushed down a toilet

Methodology Applied
Scientific EffectWater solubility: Solvation

Implementation Method 2

the aqueous chemical agent includes a cross-linking agent that causes the water-soluble binder to initiate a cross-linking reaction

Methodology Applied
Scientific EffectCross-linking reaction: Chemical Bonding

Data Source

PatentEP3305158B1Water-disintegrable sheet
Publication Date: 2020.03.25 DAIO PAPER CORP
  • EP3305158B1 patent drawingFigure 1
  • EP3305158B1 patent drawingFigure 2A~2B
  • EP3305158B1 patent drawingFigure 3A~3C

AI summary

A toilet cleaning sheet 100 includes a multi-ply base paper sheet that is substantially water-dispersible. The multi-ply base paper sheet contains pulp and a water-soluble binder and is impregnated with an aqueous chemical agent. The basis weight of the multi-ply base paper sheet is 30 gsm to 150 gsm, and the content of the water-soluble binder increases towards a front surface and/or a back surface.