Sheet for extraction, extraction filter, and extraction bag

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Solution Overview

Problem

Conventional extraction sheets made from nonwoven fabrics with small basis weight are difficult to handle due to their flexibility, leading to meandering issues during manufacturing and poor shape retention, resulting in defective products and unsteady stacked bags.

Innovation Solution

A multi-layered extraction sheet comprising a meltblown nonwoven fabric with low crystallinity and a spunbonded nonwoven fabric, where the meltblown layer has a softening point 30°C lower than the spunbonded layer, allowing for creasability and improved handling properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If nonwoven fabric with small basis weight is used to improve extraction rate and reduce cost, then extraction performance is improved, but the material becomes difficult to handle and machine due to high flexibility

Engineering Contradiction:
Improveextraction rateVSAvoidmachinability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent uses a laminated structure combining meltblown nonwoven fabric (providing flexibility and extraction performance) with spunbonded nonwoven fabric (providing rigidity and dimensional stability). This composite structure resolves the contradiction by integrating materials with complementary properties, allowing the filter to maintain both high extraction rate and good machinability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent controls the basis weight of the meltblown nonwoven fabric within a specific range (5-30 g/m²) to optimize the balance between flexibility for extraction and rigidity for handling. By precisely controlling material parameters, the patent achieves both high extraction performance and improved machinability.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If nonwoven fabric with small basis weight is used to improve transparency and luster, then appearance is improved, but the material becomes difficult to handle due to thinness and flexibility

Engineering Contradiction:
Improvetransparency and lusterVSAvoidhandling property
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The laminated structure combines thin meltblown nonwoven fabric (providing transparency and luster) with spunbonded nonwoven fabric (providing dimensional stability). This allows the filter to maintain improved appearance while being easier to handle during manufacturing and use.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different layers: the meltblown layer provides the desired optical properties (transparency and luster) while the spunbonded layer provides the mechanical properties (rigidity and stability) needed for handling. Each layer performs its specific function locally.

Inventive Principle:
Principle #3Local quality

3Productivity

If extraction sheet is made flexible to improve extraction rate, then extraction performance is improved, but the sheet meanders during high-speed conveyance causing defective products

Engineering Contradiction:
Improveextraction rateVSAvoidcutting and sealing line accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The laminated structure combines flexible meltblown nonwoven fabric (improving extraction rate) with rigid spunbonded nonwoven fabric (preventing meandering). The rigid layer acts as a stabilizing backbone that maintains the sheet's position during high-speed conveyance, ensuring accurate cutting and sealing lines while preserving the extraction performance of the flexible layer.

Inventive Principle:
Principle #40Composite materials

4Productivity

If extraction bags are made from flexible nonwoven fabric to improve extraction performance, then extraction rate is improved, but the stacked bags become unsteady and slip down

Engineering Contradiction:
Improveextraction rateVSAvoidstacking stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The laminated structure combines flexible meltblown nonwoven fabric (improving extraction rate) with rigid spunbonded nonwoven fabric (improving shape retention). The rigid spunbonded layer provides dimensional stability that prevents the bags from deforming when stacked, ensuring stable stacking while maintaining the high extraction performance of the flexible meltblown layer.

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 solution enhances machinability and handling properties by preventing meandering and ensuring steady stacking, while maintaining good extraction performance and sealing strength, even when immersed in hot water.

Implementation Method 1

a layer (layer M) including a meltblown nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 9.0% or lower and a fiber diameter of 15.0 μm or smaller and that has a basis weight of 2.0 to 30.0 g/m2, and a layer (layer S) including a spunbonded nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 30.0 to 60.0% and a fiber diameter of 35.0 μm or smaller and that has a basis weight of 5.0 to 30.0 g/m2

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

the extraction sheet includes a layer (layer M) including a meltblown nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 9.0% or lower... and a layer (layer S) including a spunbonded nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 30.0 to 60.0%

Methodology Applied
Scientific EffectCrystallinity difference: Crystallisation

Data Source

PatentEP3269437B1Sheet for extraction, extraction filter, and extraction bag
Publication Date: 2019.12.11 OHKI
  • EP3269437B1 patent drawingFigure 1
  • EP3269437B1 patent drawingFigure 2~3
  • EP3269437B1 patent drawingFigure 4

AI summary

An extraction sheet having high machinability in the manufacture of an extraction filter for beverages and an extraction filter using the same and having high handling property is provided. The extraction sheet comprises a layer including a meltblown nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 9.0% or lower and a fiber diameter of 15.0 µm or smaller and that has a basis weight of 2.0 to 30.0 g/m2, and a layer including a spunbonded nonwoven fabric that is formed from fibers of a polylactic acid-based resin having a crystallinity of 30.0 to 60.0% and a fiber diameter of 35.0 µm or smaller and that has a basis weight of 5.0 to 30.0 g/m2. The extraction sheet has a bending hysteresis of 5.0×10-3 to 14.5×10-3 gf·cm/cm.