Method for manufacturing core wire for transmission belt, treatment agent, and kit for treatment

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Solution Overview

Problem

Existing methods for manufacturing power transmission belts with para-aramid cords face challenges in achieving firm adhesion between fibers, particularly in twisted yarn cords, while maintaining bending fatigue resistance and fraying resistance, and imposing a small environmental load.

Innovation Solution

A method involving a first treatment agent containing a condensate of resorcin and formaldehyde, carboxy-modified latex, and a polycarbodiimide resin with carbodiimide groups, combined with a hydrophilic solvent, is used to treat the yarn, enhancing adhesion and resistance properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If adhesion treatment is performed on twisted yarn cord, then handling ease is improved, but fraying resistance and peeling resistance deteriorate due to insufficient treatment agent penetration

Engineering Contradiction:
Improvehandling easeVSAvoidfraying resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by treating the aramid fiber with a specific treatment agent containing RF condensate and water-soluble epoxy compound before twisting into yarn cord. This pre-treatment ensures that the treatment agent is already present on the fiber surface, enabling sufficient penetration and adhesion even after twisting, thereby maintaining both handling ease and fraying resistance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical parameters of the treatment agent by specifying a particular composition: RF condensate (resorcinol-formaldehyde condensate) combined with water-soluble epoxy compound in specific proportions. This parameter change enables the treatment agent to penetrate twisted yarn effectively while providing adequate adhesion, resolving the contradiction between handling ease and fraying resistance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If treatment agent is used to improve adhesion between para-aramid cord and rubber, then peeling resistance is improved, but bending fatigue resistance may deteriorate due to rigidity increase

Engineering Contradiction:
Improvepeeling resistanceVSAvoidbending fatigue resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent carefully controls the concentration and composition parameters of the treatment agent applied to the aramid fiber. By using RF condensate combined with water-soluble epoxy compound in optimized proportions, the treatment provides sufficient adhesion improvement while controlling the degree of rigidity increase, thereby maintaining bending fatigue resistance alongside enhanced peeling resistance.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If aqueous treatment agent containing rubber component is used, then environmental load is reduced, but adhesion efficiency and penetration ability deteriorate

Engineering Contradiction:
Improveenvironmental loadVSAvoidadhesion efficiency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent creates a composite treatment agent system by combining RF condensate (resorcinol-formaldehyde condensate) with water-soluble epoxy compound in an aqueous medium. This composite formulation maintains the environmental benefits of an aqueous base while the synergistic combination of components enhances both penetration ability and adhesion efficiency, overcoming the limitations of conventional aqueous treatment agents.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the aqueous treatment agent by incorporating specific ratios of RF condensate and water-soluble epoxy compound. This parameter optimization enables the aqueous formulation to achieve adhesion efficiency comparable to or exceeding organic solvent-based agents, while maintaining reduced environmental load.

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

The method achieves firm adhesion between fibers in twisted yarn cords, improves fraying resistance, maintains bending fatigue resistance, and reduces environmental impact by using a hydrophilic solvent.

Implementation Method 1

a rubber component (A2) containing a carboxy-modified latex and a curing agent (A3) containing a polycarbodiimide resin having a plurality of carbodiimide groups

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

the treatment agent can homogeneously and efficiently permeate and be impregnated between filaments of the raw yarn

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

an amino group and/or carboxy group remaining in the aramid fiber and a hydroxy group of the RF condensate homogeneously react with an epoxy group of the water-soluble epoxy compound

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3369860B1Method for manufacturing core wire for transmission belt, treatment agent, and kit for treatment
Publication Date: 2021.01.13 MITSUBOSHI BELTING LTD
  • EP3369860B1 patent drawingFigure 1~2
  • EP3369860B1 patent drawingFigure 3~4
  • EP3369860B1 patent drawing

AI summary

The present invention relates to a method for manufacturing a core wire for a transmission belt, including a first treatment step of treating untreated threads of a core wire for a transmission belt with a first treatment agent comprising: a rubber composition (A) containing a condensate (A1) of resorcin and formaldehyde, a rubber component (A2) containing carboxyl modified latex, and a hardening agent (A3) containing a polycarbodiimide resin having a plurality of carbodiimide groups; and a hydrophilic solvent (B).