Nitrile-Based Dual-Coating Rubber-Reinforcing Cord for Oil Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rubber-reinforcing cords with CSM-containing coatings fail to provide adequate protection and adhesion when exposed to oils, leading to swelling and separation from the reinforcing fiber and matrix rubber, resulting in insufficient strength and durability.
Innovation Solution
A rubber-reinforcing cord with a first coating of nitrile-based rubber and a first crosslinking agent, and a second coating of nitrile-based rubber with a second crosslinking agent, both providing enhanced oil resistance and adhesion, even in environments exposed to oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CSM-containing coating is used to protect reinforcing fiber and enhance adhesion, then protection and adhesion are improved under normal conditions, but the coating swells and separates when exposed to oil, leading to insufficient protection and adhesion
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by replacing CSM with nitrile-based rubber (NBR, HNBR, X-NBR, or X-HNBR) that has different chemical properties - specifically, nitrile-based rubber has resistance to oil and does not swell when exposed to oil, thereby maintaining protection and adhesion in oil environments
Solution Approach 2:
The patent uses composite material structure with multiple coatings: a first coating containing nitrile-based rubber as main component (50-100 mass%) and a second coating different from the first coating. This composite coating structure combines the oil resistance of nitrile-based rubber with the adhesion properties of the second coating, achieving both protection and adhesion in oil environments
2Ease of manufacture
If a single coating is used to simplify structure, then manufacturing is easier, but adhesion and protection are insufficient in oil environments
Solution Approach 1:
The patent segments the coating into two distinct layers: a first coating containing nitrile-based rubber as main component (50-100 mass%) that provides oil resistance, and a second coating different from the first coating that provides adhesion to the matrix rubber. This segmentation allows each coating to perform its specific function, with the first coating protecting against oil swelling and the second coating ensuring strong adhesion
3Strength
If CSM coating is used for adhesion, then adhesion is improved initially, but adhesion deteriorates over time in oil environments due to swelling
Solution Approach 1:
The patent changes the chemical composition from CSM to nitrile-based rubber (NBR, HNBR, X-NBR, or X-HNBR) which has inherent resistance to oil and does not swell when exposed to oil. This parameter change ensures that the adhesion strength is maintained over long periods in oil environments, as the nitrile-based rubber coating remains dimensionally stable and does not separate from the reinforcing fiber or matrix rubber
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 cord ensures long-term protection and strong adhesion of the reinforcing fiber to the matrix rubber, maintaining high strength and durability in oil-exposed environments.
Implementation Method 1
CSM is susceptible to oils, and oil particles can so easily become trapped within and between the molecules of CSM that exposure of the CSM-containing coating to an oil causes swelling of the coating. The swelling results in separation of the coating from both the reinforcing fiber and the matrix rubber
Data Source
AI summary
A rubber-reinforcing cord (30) according to the present invention includes: a reinforcing fiber or reinforcing fiber bundle (21); a first coating (22) provided to cover the reinforcing fiber or reinforcing fiber bundle (21); and a second coating (31) provided to cover the first coating (22) and be located at the outer surface of the rubber-reinforcing cord (30). The first coating (22) includes: first rubber including nitrile-based rubber as a main component; and a first crosslinking agent. The second coating (31) is a coating different from the first coating (22) and includes: second rubber consisting essentially of nitrile-based rubber; and a second crosslinking agent. The nitrile-based rubber is at least one selected from nitrile rubber, hydrogenated nitrile rubber, carboxylated nitrile rubber, and carboxylated hydrogenated nitrile rubber.