Two-Ply Tissue Paper Evaluation Using Regression-Based Sensory Metrics

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Solution Overview

Problem

Conventional sensory evaluation methods for tissue paper lack accuracy and efficiency in quantitatively assessing usability, particularly for softness and smoothness, leading to increased development time and costs due to subjective criteria variations among evaluators.

Innovation Solution

A method involving two-ply tissue paper with specific physical properties and a sensory evaluation system using free and slip sensory evaluation steps, combined with multiple regression analysis, to objectively quantify softness and smoothness based on dry and wet tensile strengths, friction coefficient, and surface roughness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional sensory evaluation methods are used to assess tissue paper usability, then subjective judgments can be obtained from multiple subjects, but measurement precision and accuracy are reduced due to varying criteria among evaluators

Engineering Contradiction:
Improveevaluation accuracyVSAvoidevaluation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical human sensory evaluation system with an optical measurement system that uses image processing to objectively assess tissue paper properties. The system captures images of tissue paper samples and uses computer vision algorithms to quantify characteristics such as softness, smoothness, and texture, eliminating subjective variability while maintaining evaluation comprehensiveness

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an image processing system as an intermediary between the tissue paper sample and the evaluation result. This intermediary captures visual information from the tissue paper and transforms it into objective quantitative data through algorithmic analysis, serving as a bridge that converts physical properties into measurable evaluation metrics without human subjectivity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conventional sensory evaluation with multiple evaluation items is performed, then comprehensive usability assessment is achieved, but evaluation time and development costs increase due to repeated adjustments

Engineering Contradiction:
Improvedevelopment speedVSAvoidevaluation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent segments the comprehensive tissue paper evaluation into distinct visual characteristics that can be independently measured and analyzed. By breaking down overall usability assessment into specific image-processable features such as surface texture, fiber distribution, and structural patterns, the system enables parallel processing of multiple evaluation dimensions simultaneously, reducing total evaluation time

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates visual copies (images) of the tissue paper samples that can be analyzed without manipulating the physical samples themselves. This allows multiple evaluation operations to be performed on digital copies simultaneously, eliminating the need for repeated physical sample preparation and handling, thereby accelerating the development iteration process

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3708055B1Tissue paper and tissue paper evaluation method
Publication Date: 2023.05.10 DAIO PAPER CORP
  • EP3708055B1 patent drawingFigure 1
  • EP3708055B1 patent drawingFigure 2
  • EP3708055B1 patent drawingFigure 3

AI summary

To provide tissue paper excellent in softness and smoothness. In tissue paper that is two-ply non-moisturizing tissue paper to which no chemical solution is applied, a basis weight per sheet is 10.0 to 18.0 g/m2, the thickness of two plies is 100 to 240 µm, a dry tensile strength in the paper horizontal direction is 70 to 180 cN/25 mm, a wet tensile strength in the paper horizontal direction is 25 to 55 cN/25 mm, and a free sensory evaluation value Ef calculated according to the following Equation 1 is 3.7 to 6.6, and a slip sensory evaluation value Es calculated according to the following Equation 2 is 5.0 to 8.2. FreesensoryevaluationvalueEf=−2.879×drytensilestrengthinpaperhorizontaldirection+6.55×wettensilestrengthinpaperhorizontaldirection+5.36 SlipsensoryevaluationvalueEs=−8.80×dynamicfrictioncoefficient−0.41×arithmeticmeansurfaceroughness+13.58