Polyamide 4 Tire Cord Fibers via Ionic Liquid Spinning

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Solution Overview

Problem

Conventional methods for spinning polyamide 4 fibers into tires face challenges due to high melting and decomposition temperatures, resulting in inadequate fiber strength, making it difficult to produce fibers with sufficient mechanical properties for tire applications.

Innovation Solution

The use of ionic liquids as solvents for polyamide 4, specifically with high Kamlet-Taft parameter β values, enables the formation of polyamide 4 fibers with enhanced strength through wet spinning, dry-wet spinning, or gel spinning processes, achieving fiber strengths of at least 920 MPa and elastic moduli of at least 5 GPa.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyamide 4 resin is spun by normal melt spinning method, then the spinning process can be performed, but the fiber strength is inadequate for tire cords

Engineering Contradiction:
Improvespinning process feasibilityVSAvoidfiber strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the fundamental spinning parameter from melt spinning to wet spinning, which allows processing at lower temperatures that prevent decomposition. This parameter change enables the formation of high-strength polyamide 4 fibers with tensile strength of at least 920 MPa, resolving the contradiction between process feasibility and fiber strength.

Inventive Principle:
Principle #35Parameter changes

2Strength

If wet spinning or dry-wet spinning is used to avoid thermal decomposition, then the fiber strength improves, but the fiber strength is still inadequate for tire cord applications

Engineering Contradiction:
Improvefiber strengthVSAvoidspinning process complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces ionic liquids as intermediary solvents for wet spinning. These ionic liquids enable the dissolution and processing of polyamide 4 resin at low temperatures without decomposition, achieving fiber strengths of at least 920 MPa. This intermediary approach resolves the contradiction by providing a manufacturing method that is both effective and suitable for industrial production.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional solvents are used for wet spinning of polyamide 4 resin, then fiber formation is achieved, but the fiber strength remains insufficient for tire applications

Engineering Contradiction:
Improvefiber formation capabilityVSAvoidfiber strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the solvent parameter from conventional solvents to ionic liquids, which have unique properties enabling superior dissolution and processing of polyamide 4 resin. This parameter change in solvent type allows achieving fiber strengths of at least 920 MPa while maintaining ease of manufacture through wet spinning processes.

Inventive Principle:
Principle #35Parameter changes

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

This approach allows for the production of tires with improved strength and durability by creating polyamide 4 fibers with exceptional mechanical properties, suitable for use in tire cords, enhancing both high-speed durability and uniformity.

Implementation Method 1

The solvent in which the polyamide 4 resin is dissolved is required to have excellent dissolving ability with respect to the polyamide 4 resin. Consequently, investigation is being conducted into solvents that, in wet spinning or dry-wet spinning, have high dissolving ability with respect to polyamide 4

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentEP3138698B1tire
Publication Date: 2018.12.26 BRIDGESTONE CORP
  • EP3138698B1 patent drawingFigure 1~2
  • EP3138698B1 patent drawingFigure 3~4
  • EP3138698B1 patent drawing

AI summary

Provided is a tire having improved strength through use of polyamide 4 fiber. The tire contains a fiber-rubber composite including polyamide 4 fiber that contains polyamide 4.