Polyester Nonwoven Filter Sheet for Fast Sealing Without Deformation
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Solution Overview
Problem
Existing nonwoven fabric sheets with spunbonded and meltblown layers face challenges in achieving high sealing strength and machinability for fast forming machines, particularly due to issues with adhesive strength, tensile strength, and thermal resistance, leading to incomplete bonding and deformation during high-temperature processing.
Innovation Solution
A nonwoven fabric sheet with a spunbonded layer having a polyester-based resin with specific crystallinity, crystalline orientation, and birefringence, combined with a meltblown layer of low crystallinity polyester-based resin, allowing for partial thermocompression bonding and high fluidity upon heating, ensuring strong integration and high sealing strength without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the resin forming the meltblown nonwoven fabric has a low softening point and adequate fluidity, then the sealing strength is improved, but the spunbonded nonwoven fabric may deform under the same high temperature
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallinity and molecular weight of the polyester resin in the spunbonded layer. By setting crystallinity to 30-80% and IV value to 0.60-1.00, the resin maintains high melting point and thermal resistance, preventing fabric deformation during sealing processes
Solution Approach 2:
The patent uses composite materials by creating a two-layer nonwoven fabric structure where the spunbonded layer (with high thermal resistance) and meltblown layer (with low softening point) are laminated together. This composite structure allows each layer to perform its specific function: the spunbonded layer maintains shape while the meltblown layer provides sealing strength
2Productivity
If the nonwoven fabric sheet is sealed quickly in fast forming machines, then the productivity is improved, but the sealing strength may be insufficient due to inadequate bonding time
Solution Approach 1:
The patent applies phase transitions by utilizing the melting behavior of the meltblown layer resin. When heated, the resin transitions from solid to liquid state, flowing into the spunbonded layer to create strong bonding. This phase change enables rapid sealing with adequate bonding strength, supporting high-speed forming machine operations
Solution Approach 2:
The patent changes the physical parameters of the resin by controlling its crystallinity (0-14%) and molecular weight (IV value 0.30-0.80). These parameter adjustments ensure the resin has low softening point and high fluidity, allowing it to melt quickly and infiltrate the spunbonded layer rapidly, achieving both fast sealing and strong bonding
3Shape
If the spunbonded nonwoven fabric has high thermal resistance to maintain fiber form, then the shape retention is improved, but the sealing strength decreases due to inadequate resin fluidity
Solution Approach 1:
The patent applies segmentation by dividing the nonwoven fabric into two distinct layers with different functional characteristics. The spunbonded layer is optimized for shape retention with high crystallinity, while the meltblown layer is optimized for sealing with low crystallinity. This segmentation allows each layer to excel at its specific function without compromising the other
Solution Approach 2:
The patent uses composite materials by laminating two different nonwoven fabric types together. The spunbonded nonwoven fabric (with high thermal resistance) serves as the base layer for shape maintenance, while the meltblown nonwoven fabric (with low softening point) is applied as the sealing layer, creating a composite structure that combines both properties
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 enables high sealing strength and excellent machinability in fast forming machines, maintaining shape retention and transparency, with low boiling water shrinkage and improved extraction performance, suitable for extraction filters and bags.
Implementation Method 1
the meltblown nonwoven fabric layer requires that the fibers forming the meltblown nonwoven fabric is readily softened and fluidized by heating
Implementation Method 2
the fluidized resin readily infiltrates into the space among fibers in the spunbonded nonwoven fabric
Implementation Method 3
a partial thermocompression bonding section having a thermocompression bonding area rate of 5% to 30%
Data Source
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AI summary
The present invention provides a nonwoven fabric sheet for use in extraction filters having high sealing strength and extraction filters manufactured using the nonwoven fabric sheet. The nonwoven fabric sheet includes a first layer including a spunbonded nonwoven fabric formed from a polyester-based resin having an IV value of 0.60 to 1.00, a crystallinity of 30% to 80%, a crystalline orientation of 60% to 95%, and a birefringence (An) of 0.040 to 0.100 and provided with a partial thermocompression bonding section whose thermocompression bonding area rate is in the range of 5% to 30%, and a second layer including a meltblown nonwoven fabric formed from a polyester-based resin blown onto a surface of the first layer and solidified to have a crystallinity of 0% to 14%. The extraction filters are formed by sealing by welding the nonwoven fabric sheet with the second layer of the sheet placed inside.