Modified Conjugated Diene Polymer for Tire Tread Rigidity
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Solution Overview
Problem
Conventional vulcanized rubber compositions using modified conjugated diene-based polymers achieve a balance between hysteresis loss and wet skid resistance but fall short in rigidity and abrasion resistance, necessitating improvements for enhanced performance in tires and related applications.
Innovation Solution
A manufacturing process involving the reaction of active polymer terminals with a glycidylamino group-containing low molecular compound and its oligomer as modifying agents, in specific proportions, to produce a modified conjugated diene-based polymer that excels in wet skid characteristics, low hysteresis loss, abrasion resistance, and rigidity when blended with reinforcing fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional modified polymers are used to improve the balance between hysteresis loss and wet skid resistance, then the hysteresis loss is reduced and wet skid resistance is maintained, but the rigidity and abrasion resistance are insufficient
Solution Approach 1:
The patent changes the chemical structure parameters of the polymer by introducing specific modifying groups (glycidylamino groups and hydroxyl groups) at controlled ratios. This structural modification enables the polymer to simultaneously achieve low hysteresis loss and high rigidity/abrasion resistance, resolving the contradiction between energy loss and strength properties.
Solution Approach 2:
The patent creates a composite molecular structure within the polymer chain by incorporating both glycidylamino groups and hydroxyl groups as modifying groups. This composite approach at the molecular level allows the material to exhibit multiple desirable properties simultaneously, including low hysteresis loss and high rigidity with improved abrasion resistance.
2Strength
If the molecular weight is increased to improve rigidity, then the rigidity of vulcanized rubber is enhanced, but the processing complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of simply increasing molecular weight, the patent changes the chemical composition parameters by introducing specific modifying groups (glycidylamino and hydroxyl groups) at controlled ratios. This approach enhances rigidity through chemical structure modification rather than molecular weight increase, thereby avoiding the associated processing difficulties.
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 resulting vulcanized rubber exhibits improved balance among wet skid characteristics, low hysteresis loss, abrasion resistance, and breaking strength, with enhanced rigidity, making it suitable for tire applications and other rubber products like footwear and vibration damping materials.
Implementation Method 1
reacting active terminals of a polymer with a glycidylamino group-containing low molecular compound and an oligomer of a dimer or more of the low molecular compound as modifying agents
Data Source
AI summary
The present invention has an object to provide a conjugated diene-based polymer, subjected to a vulcanization treatment to make a vulcanized rubber, the vulcanized rubber useful as a material for tire treads excellent in the balance among wet skid characteristics, low hysteresis loss, abrasion resistance, breaking strength and rigidity, and to provide its manufacturing process. According to the present invention, there is provided the process for manufacturing a modified conjugated diene-based polymer having a modifying group in its molecule, the process including a step of obtaining a conjugated diene-based polymer by polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, by using an alkaline metal-based initiator or an alkaline earth metal-based initiator in a hydrocarbon solvent, and a step of reacting active terminals of the polymer with a glycidylamino group-containing low molecular compound having two or more tertiary amino groups and three or more glycidyl groups bonded to the amino groups in a molecule of the compound, and an oligomer of a dimmer or more of the low molecular compound as modifying agents, wherein the reaction is performed using 75 to 95% by mass of the low molecular compound and 25 to 5% by mass of the oligomer based on the total amount of the modifying agents.