Printed Paper Wrapping Sheet for Non-Slip Absorbent Article Stacks

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Solution Overview

Problem

Individually-wrapped absorbent articles using paper wrapping sheets with high smoothness for printing operability tend to slip when stacked, leading to reduced production efficiency and a cheap appearance impression.

Innovation Solution

The wrapping sheet has a mean deviation of friction (MMD) of 0.050 or less before printing and a coefficient of static friction of 0.60 or greater after printing, with a blending ratio of recycled fibers at 20% or greater, and may include fiber bundles to prevent slipping and maintain a premium appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If paper with high surface smoothness is used as a wrapping sheet, then printing operability is improved, but the individually-wrapped absorbent articles are likely to slip against one another when stacked

Engineering Contradiction:
Improveprinting operabilityVSAvoidproduction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the MMD of the paper surface before printing to be 0.050 or less, and ensuring the coefficient of static friction after printing is 0.60 or greater. This quantitative parameter control allows the paper to achieve both high printing operability (through smoothness) and adequate anti-slip performance (through friction coefficient), resolving the contradiction between printing quality and stacking stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by incorporating fiber bundles into the paper structure. These fiber bundles create surface irregularities that increase the coefficient of static friction to 0.60 or greater, while the base paper maintains high smoothness for printing. This composite structure combines the benefits of smooth printing surface with enhanced anti-slip properties, solving the contradiction between printing operability and production efficiency.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If paper with high surface smoothness is used as a wrapping sheet, then printing operability is improved, but the appearance and texture give an impression as if it is cheap

Engineering Contradiction:
Improveprinting operabilityVSAvoidappearance quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent resolves this contradiction by changing the surface parameter metrics: MMD before printing is controlled at 0.050 or less for smooth printing, while the coefficient of static friction after printing is maintained at 0.60 or greater. This dual parameter control ensures both excellent printing operability and a premium tactile appearance, preventing the cheap impression that would result from overly smooth surfaces.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials with fiber bundles embedded in the paper structure. These fiber bundles create subtle surface irregularities that provide tactile richness and a premium feel, while the overall surface remains smooth enough for high-quality printing. This composite approach eliminates the cheap appearance association with smooth copy paper while maintaining printing operability.

Inventive Principle:
Principle #40Composite materials

3Reliability

If recycled fibers are used in the wrapping sheet, then environmental friendliness is improved, but the coefficient of static friction may be insufficient

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidanti-slip performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent successfully combines recycled fibers with fiber bundles to create a composite paper structure. The recycled fibers provide environmental friendliness, while the incorporated fiber bundles create surface irregularities that increase the coefficient of static friction to 0.60 or greater. This composite approach maintains anti-slip performance despite using recycled materials, resolving the contradiction between environmental friendliness and friction performance.

Inventive Principle:
Principle #40Composite materials

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

Achieves both high printing operability and prevents slipping of stacked absorbent articles, maintaining a premium appearance and enhancing production efficiency.

Implementation Method 1

the exposed surface after the printing has a coefficient of static friction of 0.60 or greater against an exposed surface of another individually-wrapped absorbent article

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4691435A1Individually packaged absorbent article and method for manufacturing packaged product accommodating same in package
Publication Date: 2026.02.11 DAIO PAPER CORP
  • EP4691435A1 patent drawingFigure 1
  • EP4691435A1 patent drawingFigure 2
  • EP4691435A1 patent drawingFigure 3

AI summary

An individually-wrapped absorbent article includes a wrapping sheet including paper, and an absorbent article individually wrapped with the wrapping sheet. Printing is provided on an exposed surface of the wrapping sheet, which is exposed when the wrapping sheet individually wraps the absorbent article. The exposed surface has MMD of 0.050 or less before printing, and the exposed surface after the printing has a coefficient of static friction of 0.60 or greater against an exposed surface of another individually-wrapped absorbent article.