Extraction bag, method for manufacturing extraction bag, sheet for extraction bag, and method for manufacturing sheet for extraction bag
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Solution Overview
Problem
Existing extraction bags face challenges in joining biodegradable polylactic acid resin-based nonwoven fabric sheets with accessory members without damaging the fabric, due to differences in melting points and adhesion forces.
Innovation Solution
The extraction bag incorporates a spunbond nonwoven fabric layer with a polylactic acid resin and an accessory member, where a laminate layer with a lower degree of crystallinity polylactic acid resin is used on the accessory member, allowing for controlled joining without damaging the fabric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polylactic acid resins of identical materials are used for both the nonwoven fabric and accessory member laminate, then biodegradability and environmental friendliness are improved, but the nonwoven fabric fibers are damaged during heating for attachment
Solution Approach 1:
The patent applies local quality by creating a laminate layer with different crystallinity properties than the base nonwoven fabric. The laminate layer has lower crystallinity (1-40%) compared to the spunbond layer (30-60%), allowing it to soften at lower temperatures during heating. This localized property difference enables the laminate to be thermally activated for bonding while the higher-crystallinity fabric layer maintains its structural integrity and resists fiber damage.
Solution Approach 2:
The patent changes the crystallinity parameter of the polylactic acid resin between different layers. By controlling the crystallinity of the laminate layer to be lower than that of the spunbond layer, the patent creates a temperature gradient in material softening behavior. The heating process exploits this parameter difference, softening only the laminate layer at temperatures below the fabric's melting point, thus enabling bonding without damaging the fabric fibers.
2Reliability
If the adhesion force of the accessory member to the bag body is increased, then manufacturing reliability is improved, but holes are created in the sheet when the accessory member is peeled off
Solution Approach 1:
The laminate layer serves as a localized bonding interface with controlled adhesion properties. Its lower crystallinity creates a softer, more compliant region that can form strong bonds with the fabric during heating. When peeling occurs, the damage localizes to this laminate layer rather than propagating through the entire sheet, preventing holes in the main bag body while maintaining attachment reliability during use.
Solution Approach 2:
The laminate layer acts as an intermediary between the accessory member and the nonwoven fabric. It provides a controlled adhesion interface that balances bonding strength and release characteristics. The laminate's lower crystallinity makes it the preferred location for bond formation and subsequent failure, protecting the main sheet from damage while ensuring reliable attachment during the extraction process.
3Strength
If the adhesion force of the accessory member to the bag body is decreased, then sheet integrity is improved, but the accessory member drops off during filling
Solution Approach 1:
The patent changes the crystallinity parameter to control adhesion force. The lower crystallinity of the laminate layer (1-40%) compared to the spunbond layer (30-60%) creates optimal bonding conditions. This parameter adjustment ensures sufficient adhesion force to hold the accessory member during filling and extraction operations, while the controlled nature of this bonding prevents excessive force that would damage the sheet upon peeling.
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 solution enables the integration of accessory members with the spunbond nonwoven fabric layer while maintaining the filter functionality and structural integrity of the fabric, thus reducing environmental impact.
Implementation Method 1
a degree of crystallinity of the polylactic acid resin contained in the laminate layer is set to be smaller than a degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer
Data Source
AI summary
Provided is an extraction bag in which an accessory member can be appropriately joined to a sheet constituting the extraction bag, even in a case where biodegradable polylactic acid resins are adopted as a resin for a nonwoven fabric for use in the sheet and as a resin for a laminate for use in the accessory member of the extraction bag, without damaging the nonwoven fabric side. An extraction bag 100 including a spunbond nonwoven fabric layer 10 containing a polylactic acid resin and an accessory member 20 which are joined, wherein a laminate layer 21 containing a polylactic acid resin is provided on at least a surface of the accessory member 20 in contact with the spunbond nonwoven fabric layer 10, and wherein a degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 is set to be smaller than a degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10.