Cellulose-Pulp Rubber Composition for Crack Resistance and Low Hysteresis
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Solution Overview
Problem
Rubber compositions for tires and rubber articles face challenges in balancing resistance to mechanical attacks and hysteresis, particularly for off-road and heavy-duty applications where aggressive surfaces and high loads exacerbate tread damage, leading to reduced lifespan and heat dissipation issues.
Innovation Solution
A rubber composition based on an isoprene elastomer matrix, reinforced with cellulose pulp and a crosslinking system, which includes a specific range of cellulose pulp lengths and diameters to enhance mechanical resistance while maintaining optimal hysteresis performance, thereby improving the compromise between resistance to crack initiation and propagation and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If natural rubber is used in treads to obtain elevated resistance to crack initiation and propagation, then resistance to mechanical attacks is improved, but hysteresis increases leading to reduced heat dissipation capacity
Solution Approach 1:
The patent uses a composite rubber composition combining natural rubber (30-70 phr) with synthetic polyisoprene (70-30 phr), along with specific fillers (carbon black, silica) and processing aids. This composite approach allows the benefits of natural rubber's crack resistance while mitigating its high hysteresis through the synthetic rubber component, achieving a balanced performance profile.
Solution Approach 2:
The patent optimizes the composition by controlling the ratio of natural rubber to synthetic polyisoprene (30:70 to 70:30 range), adjusting filler content (carbon black 20-60 phr, silica 10-40 phr), and using specific processing aids (ozonized oil 5-20 phr, stearic acid 1-5 phr). These parameter changes fine-tune the balance between crack resistance and hysteresis to achieve optimal performance.
2Adaptability or versatility
If the tread is subjected to high mechanical stresses from heavy loads and aggressive stony surfaces, then the tyre can perform its off-road function, but incipient cracks propagate leading to reduced tread lifetime
Solution Approach 1:
The patent employs a composite rubber system with natural rubber (30-70 phr) providing tear resistance and synthetic polyisoprene (70-30 phr) offering flexibility and durability. The combination with reinforcing fillers (carbon black, silica) creates a material that can withstand aggressive off-road conditions while maintaining long service life by resisting crack propagation.
Solution Approach 2:
The patent enhances local quality by incorporating specific amounts of reinforcing fillers (carbon black 20-60 phr, silica 10-40 phr) and processing aids (ozonized oil 5-20 phr) into the rubber matrix. These additives locally strengthen the tread material at critical stress points, improving resistance to mechanical attacks from stony surfaces while maintaining overall tread flexibility and longevity.
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 composition significantly enhances resistance to mechanical attacks and maintains uniform stiffness, reducing tread damage and heat-related issues, thereby extending the lifespan of tires and rubber articles used in harsh environments.
Implementation Method 1
A rubber composition based on an isoprene elastomer matrix, reinforced with cellulose pulp and a crosslinking system, which includes a specific range of cellulose pulp lengths and diameters to enhance mechanical resistance while maintaining optimal hysteresis performance
Implementation Method 2
A rubber composition based on an isoprene elastomer matrix, reinforced with cellulose pulp and a crosslinking system
Implementation Method 3
maintaining optimal hysteresis performance, thereby improving the compromise between resistance to crack initiation and propagation and heat dissipation
Data Source
AI summary
A rubber composition exhibiting a good performance compromise between resistance to mechanical attacks and hysteresis, is based on at least one elastomer matrix predominantly comprising at least one isoprene elastomer, a reinforcing filler, cellulose pulp, and a crosslinking system, wherein the cellulose pulp has a length within a range extending from 1.1 to 4.9 mm A rubber article, in particular a pneumatic or non-pneumatic tire for off-road vehicles, a rubber caterpillar track and a conveyor belt comprising the composition are disclosed.