Sheet for extraction, extraction filter, and extraction bag
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Solution Overview
Problem
Conventional extraction sheets made of 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 with higher crystallinity, allowing for creasability and improved handling properties, with a softening point difference between the layers enabling effective welding and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a nonwoven fabric with small basis weight is used to improve extraction rate and reduce cost, then the extraction sheet becomes thin and flexible, but the machinability deteriorates due to difficulty in handling and meandering during high-speed conveyance
Solution Approach 1:
The invention changes the physical parameters of the nonwoven fabric by controlling the crystallinity of the polylactic acid-based resin to be 9.0% or lower. This parameter change transforms the material from a highly flexible, difficult-to-handle state to a creasable, easy-to-manage state while maintaining the thin and flexible structure needed for high extraction rate.
Solution Approach 2:
The invention uses a composite structure consisting of a nonwoven fabric layer and a film layer laminated together. The nonwoven fabric provides extraction functionality while the film layer provides structural stability and creasability. This composite material approach resolves the contradiction between flexibility for extraction and stability for manufacturing.
2Ease of manufacture
If a nonwoven fabric with small basis weight is used to decrease cost and improve appearance, then the extraction sheet becomes thin and flexible, but the handling property deteriorates due to easy deformation and unsteady stacking
Solution Approach 1:
By controlling the crystallinity parameter of the polylactic acid-based resin to be 9.0% or lower, the invention achieves a unique state where the material is both creasable and maintains shape after creasing. This enables the thin, flexible extraction sheet to be handled easily and stacked stably without compromising cost-effectiveness or appearance.
Solution Approach 2:
The invention applies a preliminary crease line to the extraction sheet before stacking. This preliminary action of creasing stabilizes the flexible extraction sheet, preventing deformation during stacking and conveying operations, thereby improving handling property while maintaining the cost and appearance benefits of using thin nonwoven fabric.
3Ease of manufacture
If the extraction sheet is made creasable like paper to prevent meandering, then the machinability improves, but the material structure must be fundamentally changed from conventional nonwoven fabric
Solution Approach 1:
The invention achieves creasability by changing the crystallinity parameter of the polylactic acid-based resin to 9.0% or lower, which fundamentally alters the material structure from conventional nonwoven fabric. This parameter change enables the extraction sheet to be creased like paper, preventing meandering during high-speed conveyance and improving machinability.
Solution Approach 2:
The invention creates a composite material structure combining a nonwoven fabric layer with a film layer. This composite structure provides the creasability needed for improved machinability while maintaining the extraction functionality of the nonwoven fabric. The lamination of different materials resolves the complexity issue by combining their complementary properties.
4Strength
If a meltblown nonwoven fabric with high crystallinity is used to provide rigidity and prevent powder leakage, then the mechanical strength improves, but the creasability deteriorates
Solution Approach 1:
The invention inverts the conventional approach by using a meltblown nonwoven fabric with very low crystallinity (9.0% or lower) instead of high crystallinity. This parameter change sacrifices some rigidity but gains creasability, allowing the material to be folded and creased during manufacturing without breaking or resisting deformation.
Solution Approach 2:
The invention compensates for the reduced rigidity of low-crystallinity meltblown fabric by laminating it with a film layer. This composite structure provides the necessary mechanical strength and sealing strength while the low-crystallinity meltblown layer provides the creasability needed for manufacturing.
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 creasable extraction sheet prevents meandering during manufacturing, enhances product appearance, and provides stable, stackable bags with high handling properties and efficient extraction performance.
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 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%... the extraction sheet has a bending hysteresis of 5.0×10−3 to 14.5×10−3 gf·cm/cm
Data Source
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 includes 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.