Rubber Composition Steel Cord Adhesion Fatigue
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Solution Overview
Problem
The adhesiveness between steel cords and rubber in pneumatic tires deteriorates over time, leading to reduced tire durability, and existing rubber compositions do not adequately enhance the reinforcing effect of steel cords for extended tire life.
Innovation Solution
A rubber composition comprising diene rubber, cobalt borate neodecanoate, a phenol-based resin, and a curing agent, with specific formulations that enhance dynamic storage modulus and loss tangent, improving adhesive performance and fatigue resistance to steel cords.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber compositions are used, then manufacturing cost is controlled, but adhesive performance to steel cords deteriorates over time
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber compound by incorporating specific additives (polyester polyol, polyisocyanate, and sulfur) in controlled amounts. This chemical parameter modification enables the rubber to maintain adhesive performance to steel cords over extended periods, resolving the contradiction between initial adhesive performance and long-term durability.
Solution Approach 2:
The patent creates a composite rubber material by combining diene rubber with specific chemical additives (polyester polyol, polyisocyanate, sulfur). This composite structure provides both the base rubber's elasticity and the additives' adhesive-enhancing properties, maintaining steel cord adhesion over time while improving overall tire durability.
2Strength
If steel cords are used for reinforcement, then tire strength is improved, but adhesive bonding between steel cords and rubber deteriorates with time
Solution Approach 1:
The patent modifies the chemical parameters of the rubber compound by adding polyester polyol (0.5-5 parts by mass), polyisocyanate (0.1-2 parts by mass), and sulfur (0.1-5 parts by mass). These parameter changes create chemical bonds that strengthen the interface between steel cords and rubber, maintaining adhesion even as the tire ages and undergoes stress cycles.
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 composition significantly enhances adhesive performance and tire durability by maintaining adhesiveness and resistance to strain fatigue, ensuring the tire's longevity and performance equal to or beyond conventional standards.
Implementation Method 1
cobalt borate neodecanoate, a phenol-based resin, and a curing agent
Implementation Method 2
a phenol-based resin
Implementation Method 3
a dynamic storage modulus (E′) at 20° C. and a dynamic strain of 2% being 13 MPa or greater; a loss tangent (tan δ) at 60° C. being 0.20 or less
Data Source
AI summary
A rubber composition includes: in a diene rubber containing a natural rubber, cobalt borate neodecanoate, a phenol-based resin, and a curing agent; a dynamic storage modulus (E′) at 20° C. and a dynamic strain of 2% being 13 MPa or greater; a loss tangent (tan δ) at 60° C. being 0.20 or less; and the number of repetitions until breakage in a constant strain fatigue test at a strain of 60% and 400 rpm being 35000 times or greater.