Rubber-Reinforcing Cord Coating for Adhesion and Bending Fatigue
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rubber-reinforcing cords for rubber products, particularly those with hydrogenated nitrile rubber matrix, face challenges in achieving strong adhesion and bending performance due to the need for multiple coatings, which can lead to decreased bending fatigue resistance from excessive crosslinking agents or rigid coatings.
Innovation Solution
A rubber-reinforcing cord with a single coating comprising carboxyl-modified nitrile rubber, isocyanate compound, bismaleimide compound, carbon black, and rubber-modified epoxy resin, where the isocyanate compound is 10 to 50 parts, bismaleimide is 5 to 25 parts, carbon black is 2 to 18 parts, and rubber-modified epoxy resin is 5 to 30 parts by mass, providing strong adhesion and improved bending performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional first coating including chlorosulfonated polyethylene is used to achieve adhesion to hydrogenated nitrile rubber, then adhesion is improved, but the coating becomes hard and rigid which decreases bending fatigue resistance
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by introducing carboxyl-modified nitrile rubber with specific carboxyl content (0.1-1.0 mmol/g) and controlling the ratio of rubber latex to resorcinol-formaldehyde condensate. This parameter optimization allows the coating to achieve both adhesion to hydrogenated nitrile rubber and flexibility for bending fatigue resistance, resolving the contradiction between strength and reliability
Solution Approach 2:
The patent creates a composite coating system combining rubber latex (providing flexibility and adhesion) with resorcinol-formaldehyde condensate (providing crosslinking and strength). This composite approach allows the coating to simultaneously achieve adhesion to the rubber matrix and maintain bending fatigue resistance through the synergistic effects of the combined materials
2Strength
If a large amount of crosslinking agent is added to the first coating to achieve adhesion, then adhesion to hydrogenated nitrile rubber is improved, but the coating becomes hard which decreases bending fatigue resistance
Solution Approach 1:
The patent optimizes the crosslinking density by controlling the carboxyl content of the modified nitrile rubber (0.1-1.0 mmol/g) and the ratio of crosslinking agents. This precise parameter control achieves sufficient adhesion while maintaining coating flexibility, preventing the excessive hardening that would reduce bending fatigue resistance
Solution Approach 2:
The patent creates local quality differentiation within the coating by having the rubber latex component provide flexibility and adhesion at the interface with the rubber matrix, while the resorcinol-formaldehyde condensate provides crosslinking strength in the coating structure. This localized functional distribution resolves the contradiction between adhesion strength and bending flexibility
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 rubber-reinforcing cord achieves strong adhesion and high bending performance without multiple coatings, enhancing the durability and flexibility of rubber products, particularly those with hydrogenated nitrile rubber matrix.
Implementation Method 1
the coating includes a rubber component including at least one selected from the group consisting of carboxyl-modified nitrile rubber and carboxyl-modified hydrogenated nitrile rubber, an isocyanate compound, a bismaleimide compound
Implementation Method 2
the content of the carbon black is 2 to 18 parts by mass
Implementation Method 3
carbon black, and a rubber-modified epoxy resin
Implementation Method 4
a rubber-modified epoxy resin, and in the coating, the content of the isocyanate compound is 10 to 50 parts by mass
Data Source
Figure 1~2
Figure 3~4
AI summary
A rubber-reinforcing cord (12) of the present invention includes at least one strand. The strand includes at least one filament bundle and a coating provided to cover at least a portion of a surface of the filament bundle. The coating includes a rubber component including at least one selected from the group consisting of carboxyl-modified nitrile rubber and carboxyl-modified hydrogenated nitrile rubber, an isocyanate compound, a bismaleimide compound, carbon black, and a rubber-modified epoxy resin. In the coating, the content of the isocyanate compound is 10 to 50 parts by mass, the content of the bismaleimide compound is 5 to 25 parts by mass, the content of the carbon black is 2 to 18 parts by mass, and the content of the rubber-modified epoxy resin is 5 to 30 parts by mass, with respect to 100 parts by mass of the rubber component.