Paper Sachet Rupture Using Swelling Absorbent and Soluble Adhesive

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Solution Overview

Problem

Conventional sachets used for sanitary purposes in hospitals, whether made of water-permeable paper or water-soluble synthetic polymers, face challenges in achieving a high rupture rate during exposure to liquids, with paper sachets being inefficient and prone to failure, especially with thick liquids, while synthetic polymer sachets are costly and inefficient in manufacturing.

Innovation Solution

A sachet design utilizing a sheet of material fastened with a water-soluble, heat-activatable adhesive containing dry granules of sodium polyacrylate that swells upon liquid exposure, ensuring a high rupture rate and efficient manufacturing, with optional perforations and lacquer coating to control liquid penetration and enhance paper strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If paper sachets are used for high manufacturing efficiency and low cost, then manufacturing productivity is improved, but rupture reliability deteriorates

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidburst rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a water-soluble adhesive as an intermediary layer between the paper sheets and the superabsorbent material. This adhesive layer acts as a controlled weak point that facilitates reliable rupture when exposed to liquid, while not interfering with the manufacturing process. The adhesive mediates between the need for strong paper (for manufacturing) and the need for easy rupture (for functionality).

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter of the adhesive's water solubility and bond strength to create a controlled failure mechanism. By selecting an adhesive that maintains strong bonds during manufacturing but weakens and fails reliably when exposed to liquid, the system achieves both high manufacturing efficiency and high rupture reliability. The adhesive's properties are specifically tuned to fail at a predictable stress threshold when wetted.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If lower tensile strength paper is used to increase rupture likelihood, then burst rate is improved, but manufacturing reliability deteriorates

Engineering Contradiction:
Improveburst rateVSAvoidmanufacturing process stability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the sachet structure into distinct functional layers: strong paper sheets for manufacturing stability, and a separate adhesive layer for controlled rupture. This segmentation allows each component to be optimized independently - the paper can be strong enough for manufacturing while the adhesive provides the rupture function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The water-soluble adhesive serves as an intermediary that decouples the tensile strength requirements from the rupture requirements. The paper maintains high tensile strength for manufacturing, while the adhesive layer becomes the controlled weak point that fails reliably when exposed to liquid, eliminating the need to use weak paper.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If synthetic polymer sachets are used to ensure 100% release rate, then rupture reliability is improved, but manufacturing cost and efficiency deteriorate

Engineering Contradiction:
Improverelease rateVSAvoidmanufacturing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent creates a composite sachet structure combining paper (for manufacturing efficiency) with a water-soluble adhesive layer (for reliable rupture). This composite approach achieves the 100% release rate of synthetic polymers while maintaining the manufacturing advantages of paper, as the adhesive layer ensures complete material release when wetted.

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

The sachet design ensures a high rupture rate and efficient absorption of liquids, minimizing failure and enabling cost-effective, efficient manufacturing, with sodium polyacrylate granules effectively dispersing to maximize absorption capacity.

Implementation Method 1

the fastening means comprises a water-soluble, heat activatable adhesive which weakens on exposure to liquid

Methodology Applied
Scientific EffectWater solubility: Solvation

Implementation Method 2

containing a quantity of dry granules of sodium polyacrylate capable of absorbently swelling to exceed the volume of the sachet when the sachet is exposed to liquid

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

sodium polyacrylate capable of absorbently swelling to exceed the volume of the sachet

Methodology Applied
Scientific EffectSwelling: Hydrogel

Implementation Method 4

the fastening means comprises a water-soluble, heat activatable adhesive which weakens on exposure to liquid

Methodology Applied
Scientific EffectHeat activation: Heat Treatment

Data Source

PatentEP2544641B1sachet
Publication Date: 2016.04.20 DATESAND
  • EP2544641B1 patent drawingFigure 1~2
  • EP2544641B1 patent drawingFigure 3~4
  • EP2544641B1 patent drawingFigure 5~6

AI summary

A sachet defining a volume. The sachet has a sheet of material fastened to itself and/or another sheet of material and contains a sufficient quantity of absorbent material such that when the sachet is exposed to liquid a swelled volume of the absorbent material exceeds the volume of the sachet, and wherein the fastening means weakens on exposure to liquid. The sheet material may be paper. The absorbent material may be a super absorbent polymer. The super absorbent material may be sodium polyacrylate.