Vulcanized Rubber Composition with Double-Network Crack Resistance
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Solution Overview
Problem
Vulcanized rubber compositions used in tire and other rubber products face inadequate crack growth resistance under high strain, which limits their durability and longevity.
Innovation Solution
A method for producing a vulcanized rubber composition that involves kneading polyisoprene rubber with syndiotactic 1,2-polybutadiene at a temperature higher than the melting point of the syndiotactic 1,2-polybutadiene and vulcanizing the mixture within a specific temperature range to form a double network structure, enhancing crack growth resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dienic rubbers (BR, SBR) are used in vulcanized rubber compositions, then the composition can be easily manufactured and processed, but the crack growth resistance under high strain is insufficient
Solution Approach 1:
The patent uses a composite material system combining polyisoprene rubber with syndiotactic 1,2-polybutadiene (SPB) to achieve both high crack growth resistance and processability. The SPB component forms a double network structure within the polyisoprene matrix, creating a composite that exhibits superior durability while maintaining manufacturing feasibility through controlled kneading and vulcanization processes.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the kneading temperature (higher by 10 to 100°C than the melting point of SPB) and vulcanization temperature (within the melting point range of SPB ± 15°C). These temperature parameter optimizations enable the SPB to form the desired double network structure for improved crack growth resistance while ensuring easy processing and manufacturing.
2Reliability
If polybutadiene rubber containing syndiotactic 1,2-polybutadiene is mixed to improve crack growth resistance, then some improvement is achieved, but further improvement is desired
Solution Approach 1:
The patent applies local quality by creating a double network structure where syndiotactic 1,2-polybutadiene forms a specific network within the polyisoprene rubber matrix. This localized double network structure concentrates the crack growth resistance enhancement in the critical regions where cracks initiate and propagate, while the overall composition maintains balanced mechanical properties and strength.
3Ease of manufacture
If the syndiotactic 1,2-polybutadiene is kneaded at temperatures significantly above its melting point, then mixing efficiency improves, but excessive energy consumption and potential degradation occur
Solution Approach 1:
The patent optimizes the kneading temperature parameter to be higher by only 10 to 100°C above the melting point of syndiotactic 1,2-polybutadiene, rather than using significantly higher temperatures. This parameter optimization achieves sufficient mixing efficiency for forming the double network structure while minimizing energy consumption and preventing thermal degradation of the rubber components.
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 significantly improves the crack growth resistance of the vulcanized rubber composition, making it more durable and suitable for high-strain applications such as tires and other rubber products.
Implementation Method 1
the resultant unvulcanized rubber composition is vulcanized at a temperature falling within a range of the melting point of the syndiotactic 1,2-polybutadiene ± 15°C
Implementation Method 2
the resultant unvulcanized rubber composition is vulcanized at a temperature falling within a range of the melting point of the syndiotactic 1,2-polybutadiene ± 15°C
Data Source
AI summary
The present invention is a method for producing a vulcanized rubber composition that contains a rubber component containing a polyisoprene rubber, and a syndiotactic 1,2-polybutadiene, wherein the syndiotactic 1,2-polybutadiene and the polyisoprene rubber are kneaded at a temperature higher by 10 to 100°C than the melting point of the syndiotactic 1,2-polybutadiene, and the resultant unvulcanized rubber composition is vulcanized at a temperature falling within a range of the melting point of the syndiotactic 1,2-polybutadiene ± 15°C. The method improves the crack growth resistance of the vulcanized rubber composition.