Multi-Strand Reinforcement Cord Structure for Rust Resistance

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Solution Overview

Problem

Existing multi-strand steel cords suffer from rusting due to water permeation, which is not adequately addressed in conventional technologies, particularly when subjected to external damage.

Innovation Solution

A multi-strand elastomer reinforcement cord with a defined polymer material filling rate, having a melting point of 80°C to 160°C, is used to fill gaps between metal filaments, ensuring a minimum intra-sheath-strand filling rate of 52% and inter-strand filling rate of 75%, inhibiting rust development.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a multi-strand structure with many metal filaments is used to increase strength, then the cord strength is improved, but the rust resistance deteriorates due to more gaps between filaments

Engineering Contradiction:
Improvecord strengthVSAvoidrust resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

Resin filaments are introduced as an intermediary substance between metal filaments. These resin filaments fill the gaps and spaces between the metal filaments during cord formation, creating a barrier that prevents water and corrosive substances from reaching the metal surfaces, thereby protecting against rust while maintaining the multi-strand structure's strength

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite cord structure combining metal filaments (for strength) with resin filaments (for corrosion protection). This composite approach allows the metal filaments to provide tensile strength while the resin filaments provide rust resistance by filling gaps and preventing water permeation, solving the contradiction between strength and rust resistance

Inventive Principle:
Principle #40Composite materials

2Reliability

If resin filaments are added to fill gaps between metal filaments to improve rust resistance, then the rust resistance is improved, but the cord structure becomes more complex

Engineering Contradiction:
Improverust resistanceVSAvoidcord structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resin filaments are merged with the metal filaments in the cord formation process itself, rather than being added as a separate protective layer afterward. Both types of filaments are twisted together during the same manufacturing process, creating an integrated structure where the resin filaments naturally fill the gaps between metal filaments without requiring additional processing steps

Inventive Principle:
Principle #5Merging (Combining)

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 elastomer reinforcement cord exhibits improved rust resistance and maintains adhesive strength with elastomers, preventing water pathways and ensuring durability.

Implementation Method 1

the polymer material have a melting point or softening point of 80°C to 160°C

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the polymer material have a melting point or softening point of 80°C to 160°C

Methodology Applied
Scientific EffectSoftening:

Implementation Method 3

allowing rubber to permeate into the thus formed gaps

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3875677B1Elastomer reinforcement cord
Publication Date: 2025.12.03 BRIDGESTONE CORP
  • EP3875677B1 patent drawingFigure 1~2
  • EP3875677B1 patent drawingFigure 3~4
  • EP3875677B1 patent drawing

AI summary

Provided is an elastomer reinforcement cord with improved rust resistance. An elastomer reinforcement cord 10 includes metal filaments and a polymer material. The elastomer reinforcement cord 10 has a multi-strand structure which includes: at least one core strand 21 formed by twisting plural metal filaments 1a and 1b together; and two or more sheath strands 22 each formed by twisting plural metal filaments 11a and 11b together, the sheath strands being twisted together around the core strand. An intra-sheath-strand filling rate a, which is a ratio of the area of the polymer material with respect to an intra-sheath-strand gap region A, is 52% or higher, and an inter-strand filling rate b, which is a ratio of the area of the polymer material with respect to an inter-strand gap region B, is 75% or higher.