Single Component Polyester Monofilament Node Control
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Solution Overview
Problem
The challenge is to produce a fine-size polyester monofilament with high strength, high modulus, and uniform fiber diameter for superfine high-mesh filters, which minimizes node defects and maintains high filtration and permeation performance, as existing methods often result in node formation due to polymer degradation and gel production during the manufacturing process.
Innovation Solution
A single-component polyester monofilament is developed with specific parameters, including node diameter and number control, using solid-phase polymerization and the addition of titanium oxide, to ensure high uniformity and resistance to degradation, thereby reducing node formation and enhancing filter quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fineness of the monofilament is reduced to increase mesh count and reduce wire diameter, then filtration performance and acoustic permeability are improved, but the monofilament becomes more susceptible to node defects and yarn breakage
Solution Approach 1:
The patent applies parameter changes by precisely controlling the intrinsic viscosity of the polyester within 0.60-1.00 dL/g and the molecular weight distribution (Mw/Mn ratio between 1.8-3.5). These parameter optimizations ensure that even as fineness is reduced to increase mesh count, the monofilament maintains sufficient strength and uniformity to prevent node defects and yarn breakage, thereby resolving the contradiction between improved filtration performance and maintained reliability.
2Strength
If strength and modulus are increased through orientation and crystallization at the fiber surface, then high-strength and high-modulus properties are achieved, but scratch fluff is produced and fiber diameter uniformity deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the intrinsic viscosity parameter to 0.60-1.00 dL/g and controlling the molecular weight distribution. This parameter optimization allows the monofilament to achieve high strength and modulus through controlled orientation and crystallization while preventing excessive surface scraping that would produce scratch fluff and deteriorate fiber diameter uniformity. The balanced parameters enable both high strength and manufacturing precision to be achieved simultaneously.
3Productivity
If the mesh count is increased and wire diameter is reduced to miniaturize acoustic filters, then acoustic permeability and dustproof performance are improved, but node defects become more frequent
Solution Approach 1:
The patent applies parameter changes by controlling intrinsic viscosity within 0.60-1.00 dL/g and molecular weight distribution (Mw/Mn ratio of 1.8-3.5). These optimized parameters ensure that when mesh count is increased and wire diameter reduced for miniaturized acoustic filters, the monofilament maintains sufficient uniformity and strength to prevent node defects, thereby maintaining both high acoustic permeability and manufacturing precision.
4Manufacturing precision
If polymer residence time in the liquid supply pipe is prolonged to reduce fineness, then more polymer degradation occurs, but reducing residence time may affect processing quality
Solution Approach 1:
The patent resolves this contradiction by optimizing the intrinsic viscosity parameter to 0.60-1.00 dL/g and controlling molecular weight distribution. These parameter changes allow the polymer to be processed with appropriate residence time without excessive degradation, while still achieving the required fineness and fiber diameter uniformity. The optimized parameters balance processing conditions to minimize polymer degradation while maintaining manufacturing precision.
Data Source
Figure 1
AI summary
Provided is a single component polyester monofilament for a superfine high-mesh filter characterized in that: the total (%) diameter of nodes of 2 µm or greater present in 1 million m in the direction of monofilament fiber length with respect to the fiber diameter is expressed by Equation (1); and the monofilament has a fineness of 3.0 - 13.0 dtex, strength of 5.0 - 6.5 cN/dtex, and strength at 5% elongation of 2.7 - 3.3 cN/dtex. [Equation 1] ∑n=1kxn−x′x′×100≤10000 (xn: node diameter, x': fiber diameter, k: number of nodes included in 1 million m in the direction of fiber length) The present invention can provide a filter that has excellent monofilament uniformity without node defects and achieves excellent quality for both filterability and permeability.