Polyamide Multifilament for Knitted Lace Transparency and Strength

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing polyamide fibers with high fineness are not suitable for knitted lace as they lack transparency and have unsatisfactory texture, while increasing fineness for durability and strength compromises lace quality.

Innovation Solution

A polyamide multifilament with single-filament fineness of 0.8 dtex to 7 dtex, strength of 7.5 cN/dtex to 8.5 cN/dtex, and knot strength of 6.0 cN/dtex to 7.5 cN/dtex, produced using a method involving a spinneret, heating cylinder, cooling device, fluid swirling nozzle, and multi-stage drawing with low relaxation heat treatment, to achieve high strength, durability, and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the fineness of yarns is enhanced to make the lace pattern look beautiful, then the transparency and pattern quality improve, but the strength of the yarns decreases

Engineering Contradiction:
Improvelace transparencyVSAvoidyarn strength
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The invention divides the yarn structure into multiple fine filaments (5-20 filaments per yarn) instead of using a single thick filament. This segmentation allows the yarn to achieve both high transparency (through fine individual filaments) and high strength (through the combined effect of multiple filaments), resolving the contradiction between transparency and strength

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite construction by combining multiple polyamide filaments into a single yarn, creating a composite structure that achieves properties superior to individual filaments. The multifilament yarn provides both the transparency needed for beautiful lace patterns and the cumulative strength of multiple filaments working together

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If the fineness of yarns is enhanced to improve lace appearance, then the pattern quality improves, but the durability of the intersection part decreases due to increased stress

Engineering Contradiction:
Improvelace transparencyVSAvoidintersection part durability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

By segmenting the yarn into multiple fine filaments (5-20 filaments), the stress at intersection points is distributed across many individual filament contact points rather than concentrated on a single thick yarn. This segmentation allows the lace to maintain both high transparency and durability at stress concentration points

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the critical parameter of filament fineness to a specific range (0.8-7 dtex per filament) that optimizes both transparency and durability. This parameter change ensures that filaments are fine enough for transparency but numerous enough to distribute stress and maintain durability at intersections

Inventive Principle:
Principle #35Parameter changes

3Shape

If the fineness of single yarn is enhanced to soften the texture of the lace, then the texture quality improves, but the strength and durability decrease

Engineering Contradiction:
Improvelace texture softnessVSAvoidyarn strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The invention achieves soft texture through segmentation into multiple very fine filaments (0.8-7 dtex each), where the fine individual filaments create a soft hand feel while the multiplicity of filaments maintains overall yarn strength. The softness comes from the fine filament structure, not from reducing the total yarn strength

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multifilament composite structure allows the yarn to exhibit soft texture characteristics (from fine individual filaments) while maintaining high strength (from the combined cross-sectional area of all filaments). The composite nature enables simultaneous achievement of softness and strength

Inventive Principle:
Principle #40Composite materials

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 polyamide multifilament enables the production of knitted lace with enhanced fineness, durability, and beautiful patterns, maintaining high strength and processability while preventing filament breakage and fluffing.

Implementation Method 1

a heating cylinder for gradually cooling the filaments

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a cooling device for cooling and solidifying the filaments

Methodology Applied
Scientific EffectCooling and solidification: Freezing

Implementation Method 3

a fluid swirling nozzle device for imparting convergence to yarns by a swirling flow

Methodology Applied
Scientific EffectSwirling flow: Vortex Ring

Data Source

PatentEP3744876B1Polyamide multifilament and knitted lace manufactured using same
Publication Date: 2024.12.04 TORAY INDUSTRIES INC
  • EP3744876B1 patent drawingFigure 1
  • EP3744876B1 patent drawingFigure 2
  • EP3744876B1 patent drawingFigure 3~4

AI summary

One embodiment of the present invention provides a high-strength polyamide multifilament capable of being formed into a knitted lace which has excellent durability, on which a pattern can look really sharp, and which has excellent softness. One embodiment of the present invention relates to a polyamide multifilament characterized by having a single yarn fineness of 0.8 to 7 dtex, strength of 7.5 to 8.5 cN/dtex and knot strength of 6.0 to 7.5 cN/dtex.