Paper Packaging Seal Strength via Heated Roll Compression Bonding

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Solution Overview

Problem

Existing methods for manufacturing individually packaged absorbent articles using paper packaging sheets require additional labor and cost due to the need for separate devices and adhesive or physical engagement to form seals, as paper does not melt under normal conditions.

Innovation Solution

A method involving inward folding of absorbent articles on a paper packaging sheet and using heated rolls to compression bond the overlaid layers at a temperature of 110 to 180°C, forming seals without the need for adhesives or additional devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If paper packaging sheets are used to reduce plastics, then environmental friendliness is improved, but seal strength formation becomes difficult without additional devices or adhesives

Engineering Contradiction:
Improveplastic useVSAvoidseal formation process
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical sealing methods (adhesives, physical engagement devices) with a thermal field-based compression bonding system. Heated rolls apply both heat and pressure to the paper packaging sheet, enabling seal formation through thermal energy and compression rather than mechanical bonding agents or complex sealing mechanisms.

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

Solution Approach 2:

The patent changes the physical parameters of the paper packaging sheet by applying controlled heat (110-180°C) and compression pressure during the sealing process. This parameter change enables the paper to be compression-bonded without adhesives or additional devices, transforming it from a non-sealing material to a seal-forming material under specific thermal and mechanical conditions.

Inventive Principle:
Principle #35Parameter changes

2Strength

If adhesives or physical engagement devices are used to form seals on paper packaging sheets, then seal strength is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveseal strengthVSAvoidsealing device structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the heating function and compression bonding function into a single integrated sealing process using heated rolls. This combination eliminates the need for separate adhesive application devices or complex physical engagement mechanisms, achieving seal strength through the unified action of thermal energy and compression pressure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The paper packaging sheet itself serves as the sealing element through compression bonding when heated. The process utilizes the paper's own properties (when activated by heat and pressure) rather than requiring external adhesives or complex sealing mechanisms, making the system self-sufficient and simpler.

Inventive Principle:
Principle #25Self-service

3Strength

If conventional sealing methods are used for paper packaging sheets, then seal strength is achieved, but labor and manufacturing cost increase

Engineering Contradiction:
Improveseal strengthVSAvoidmanufacturing efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The heated rolls apply continuous heat and compression pressure along the entire sealing path in a single continuous motion. This continuous action eliminates the need for discrete adhesive application steps or complex multi-step sealing processes, maintaining consistent seal strength while improving manufacturing efficiency and reducing labor requirements.

Inventive Principle:
Principle #20Continuity of useful action

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

This approach allows for the formation of seals with sufficient strength on both edge portions of the absorbent article, reducing labor and cost while maintaining ease of opening, and providing a natural texture and reducing plastic use.

Implementation Method 1

compression bonding overlaid layers of the packaging sheet long body in a thickness direction by a pair of rolls that are heated

Methodology Applied
Scientific EffectCompression bonding: Compression

Implementation Method 2

a temperature of at least one of the rolls is 110 to 180°C

Methodology Applied
Scientific EffectThermal energy: Heating

Data Source

PatentEP4620442A1Method for manufacturing individually-packaged absorbent articles, and individually-packaged absorbent article
Publication Date: 2025.09.24 DAIO PAPER CORP
  • EP4620442A1 patent drawingFigure 1
  • EP4620442A1 patent drawingFigure 2
  • EP4620442A1 patent drawingFigure 3

AI summary

A method for producing an individually packaged absorbent article including a packaging sheet made of paper and an absorbent article individually packaged by the packaging sheet, includes disposing absorbent articles at intervals in a conveying direction on an inner surface of a packaging sheet long body, which becomes the packaging sheet made of paper, inwardly folding the packaging sheet long body along with the absorbent articles in an orthogonal direction orthogonal to the conveying direction, and compression bonding overlaid layers of the packaging sheet long body in a thickness direction by a pair of rolls that are heated, the compression bonding being applied at a position between the absorbent articles, wherein a temperature of at least one of the rolls is 110 to 180°C.