Rubber Composition Polyol Additives High Temperature Crack Resistance
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Solution Overview
Problem
Vulcanized rubber compositions exhibit poor crack resistance and elongation at high temperature, which is a concern for their application in rubber articles such as tires, as existing techniques do not adequately address these issues.
Innovation Solution
Incorporating specific types of polyols, such as linear and cyclic polyols with multiple hydroxyl groups and a favorable hydroxyl-to-carbon ratio, into the rubber composition to enhance interactions between rubber components and additives, thereby improving crack resistance and elongation at high temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional additives (carbohydrate, methoxylated methylol melamine resin, carboxylic acid cobalt salt) are used to improve adhesion and hardness, then adhesion and hardness are improved, but crack resistance and elongation at break at high temperature deteriorate
Solution Approach 1:
The patent changes the chemical parameter of the polyol component by specifying precise hydroxyl group counts (3-6 groups) and hydroxyl-to-carbon ratios (>0.5), along with controlled content (1-4 parts by mass per 100 parts rubber). This parameter optimization enables the polyol to simultaneously improve adhesion through hydrogen bonding and maintain crack resistance by preserving rubber chain flexibility at high temperatures.
Solution Approach 2:
The patent creates a composite system by combining natural rubber and/or synthetic polyisoprene with specifically selected polyols (linear and/or cyclic) that have multiple hydroxyl groups. This composite approach allows the polyol to perform multiple functions: enhancing adhesion through hydrogen bonding with steel cords while simultaneously improving elongation at break and crack resistance through favorable hydroxyl-to-carbon ratios that maintain polymer chain mobility.
2Reliability
If polyol content is increased to improve crack resistance and elongation at break, then crack resistance and elongation improve, but energy loss increases
Solution Approach 1:
The patent optimizes the polyol content parameter to a specific range (1-4 parts by mass per 100 parts rubber component) and controls the cyclic polyol content to be 5% by mass or less of the linear polyol content. This parameter control ensures sufficient crack resistance and elongation improvement while minimizing energy loss by preventing excessive polyol accumulation that would increase hysteresis.
Solution Approach 2:
The patent applies different polyol types strategically: linear polyols (1-4 parts by mass) provide bulk flexibility and crack resistance, while cyclic polyols (≤5% of linear polyol content) enhance adhesion through hydrogen bonding. This localized quality differentiation allows the composition to achieve reliable mechanical properties without excessive energy loss from uniform high polyol content throughout the rubber matrix.
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 achieves improved crack resistance and elongation at high temperature, leading to enhanced performance in rubber articles and tires without increasing energy loss.
Implementation Method 1
interactions between the rubber component and additives (those other than polyols contained in the rubber composition) can be increased
Data Source
AI summary
Disclosed is a rubber composition which comprises: a rubber component containing 30% by mass or more of a natural rubber and/or a synthetic polyisoprene; and a total of less than 10 parts by mass of a linear polyol and a cyclic polyol per 100 parts by mass of the rubber component.