Hybrid Cord Core-Wrap Structure for Tenacity and Elongation

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Solution Overview

Problem

Current fiber-reinforced rubber products face challenges in achieving a balance between high tenacity and high elongation at break, with existing materials like steel wire and para-aromatic polyamide fibers being unsuitable for applications requiring both high strength and significant deformation or expandability.

Innovation Solution

A hybrid cord is developed, comprising a core yarn of meta-aromatic polyamide fibers twisted together and at least one wrapping yarn of para-aromatic polyamide fibers wrapped around the core at a helical angle, achieving a tenacity greater than 9 grams/denier and elongation at break greater than 20%, suitable for reinforcement in rubber and elastic matrix products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If steel wire or para-aromatic polyamide fibers are used to provide high strength, then tenacity is improved, but elongation at break deteriorates

Engineering Contradiction:
ImprovetenacityVSAvoidelongation at break
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The patent applies composite materials by combining para-aromatic polyamide fibers (providing high tenacity) with nylon or polyester fibers (providing high elongation at break) to create a hybrid cord that achieves both high strength and high elongation simultaneously, resolving the contradiction between these two properties

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If nylon or polyester fibers are used to provide high elongation at break, then elongation at break is improved, but tenacity deteriorates

Engineering Contradiction:
Improveelongation at breakVSAvoidtenacity
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The hybrid cord structure combines nylon or polyester fibers (providing high elongation at break of 15-25%) with para-aromatic polyamide fibers (providing high tenacity), where each fiber type compensates for the other's weakness to achieve both high strength and high elongation

Inventive Principle:
Principle #40Composite materials

3Length of moving object

If fibers are twisted to high twist level to increase elongation at break and fatigue resistance, then elongation at break is improved, but tenacity deteriorates

Engineering Contradiction:
Improveelongation at breakVSAvoidtenacity
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The patent uses composite materials to overcome the limitation of twisted fibers. By combining twisted nylon/polyester fibers (which gain elongation and fatigue resistance from twisting) with para-aromatic polyamide fibers (which maintain high tenacity), the hybrid cord achieves both high elongation at break and high tenacity simultaneously

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 hybrid cord provides a balanced combination of tenacity and elongation at break, making it suitable for applications requiring high strength and resistance to high pressure, such as in pneumatic tires, while maintaining sufficient deformation and expandability.

Implementation Method 1

Fibers embedded in the rubber matrix serve as a reinforcing component to support the structure of the rubber product

Methodology Applied
Scientific EffectFiber reinforcement:

Implementation Method 2

a core yarn, which is formed by meta-aromatic polyamide fibers, wherein the yarn is formed by twisting multiple plies of fibers together

Methodology Applied
Scientific EffectTwisting:

Data Source

PatentEP2652184B1Hybrid cords having high tenacity and high elongation at break
Publication Date: 2018.12.12 EI DU PONT DE NEMOURS & CO
  • EP2652184B1 patent drawingFigure 1~4
  • EP2652184B1 patent drawingFigure 5~7
  • EP2652184B1 patent drawing

AI summary

A hybrid cord having a core yarn ( 100 ) of meta - aromatic polyamide fibers, and at least one wrapping yarn ( 10, 20 ) of para - aromatic polyamide fibers that wraps around the core yarn, wherein the hybrid cord has a high tenacity and high elongation at break.