Electrospun Fiber Sheet With Alternating Nozzle Charges
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Solution Overview
Problem
Existing electrospinning methods struggle to produce fiber sheets with uniform basis weight distribution and uniform mixing of fibers with different diameters, leading to uneven deposition and repulsion issues.
Innovation Solution
An electrospinning device with multiple nozzles and power sources applying different charges to the spinning solutions, producing a fiber sheet with long fibers entangled to prevent shedding and achieve uniform basis weight, using methods like electrospinning and melt blowing to create a nonwoven fabric with distinct fiber groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrospinning method is used to produce fiber sheet, then productivity is improved and nano-size fibers are obtained, but uniform basis weight distribution and uniform mixing of fibers with different diameters cannot be achieved
Solution Approach 1:
The invention divides the fiber production process into two distinct segments: electrospinning for producing fine fibers and melt blowing for producing coarse fibers. These two fiber types are then combined in a single nonwoven fabric, allowing each process to optimize its own fiber production while achieving uniform overall distribution through the combination of different fiber diameter groups
Solution Approach 2:
The invention creates a composite nonwoven fabric structure containing two distinct fiber diameter groups (fine fibers from electrospinning and coarse fibers from melt blowing). This composite structure allows the material to achieve uniform basis weight distribution by combining fibers with different properties from two different production processes
2Productivity
If electrospinning method is used to produce fiber sheet, then nano-size fibers with high productivity are obtained, but uniform mixing of fibers with different diameters is difficult to achieve
Solution Approach 1:
The invention segments the fiber production into two separate processes (electrospinning and melt blowing) that produce fibers with distinct diameter ranges. This segmentation allows each process to maintain its own optimized production parameters while ensuring uniform mixing in the final product through the natural combination of fine and coarse fiber groups
Solution Approach 2:
The invention applies local quality by creating distinct fiber diameter groups with specific characteristics - fine fibers (0.1-3μm) from electrospinning and coarse fibers (3-10μm) from melt blowing. Each group maintains its local quality characteristics while contributing to the overall uniform composition of the nonwoven fabric
3Productivity
If multiple nozzles discharge spinning solution, then productivity is improved, but repulsion issues and uneven deposition occur due to same charge application
Solution Approach 1:
The invention introduces asymmetry in the charge application system by using positive charges for odd-numbered nozzles and negative charges for even-numbered nozzles. This asymmetric charge distribution eliminates repulsion between adjacent nozzles and promotes even deposition across the entire fiber sheet, while still maintaining high productivity through multiple nozzle operation
Solution Approach 2:
The invention applies preliminary anti-action by pre-establishing alternating charge polarity patterns on multiple nozzles before fiber production begins. This preliminary configuration prevents repulsion issues and uneven deposition from occurring, allowing all nozzles to operate simultaneously with optimal deposition uniformity
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 method results in a fiber sheet with uniform basis weight distribution and mixed fiber groups, enhancing air permeability, texture, and physical properties by ensuring even deposition and entanglement of long fibers.
Implementation Method 1
a plurality of power sources for applying charge to the spinning solution
Implementation Method 2
different charges are applied to the spinning solutions discharged from the nozzles, respectively
Implementation Method 3
An electrospinning method is a technique of applying a high voltage to a solution or a melt
Implementation Method 4
a fiber sheet with long fibers entangled to prevent shedding
Data Source
AI summary
An electrospinning device includes: a plurality of nozzles that discharge a spinning solution containing a resin; and a plurality of power sources for applying charge to the solution. The power sources are connected such that different charges are applied to the solutions discharged from the nozzles, respectively. The fiber sheet is a long fiber nonwoven fabric including first fibers and second fibers that are different from the first fibers. In a histogram based on fiber diameter distributions and frequencies of the numbers of fibers, the fiber sheet has a peak where a ratio P1 of a frequency of the number of fibers of the first fibers to a frequency of the number of fibers of the second fibers is 0.01 or more and 100 or less. Alternatively, the fiber sheet has two or more peaks in the histogram, in which a ratio P2 of a frequency of the number of fibers of the first fibers at a highest peak in a range of a fiber diameter of 3 μm or less to a frequency of the number of fibers of the second fibers at a highest peak in a range of a fiber diameter of more than 3 μm is 1 or more and 1 000 or less.