Segmented Conjugated Diene Polymer for Tire Rubber
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Solution Overview
Problem
Rubber compositions with increased vinyl content in unmodified styrene-butadiene copolymers enhance low heat generation but tend to compromise abrasion resistance, and using expensive modifiers to improve both properties is necessary.
Innovation Solution
A conjugated diene polymer with a low vinyl portion (2-20% by mol) and a high vinyl portion (50% by mol or more) is developed, where the high vinyl portion is positioned at the molecular end, enhancing reactivity with silane coupling agents and maintaining abrasion resistance without the need for modifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If vinyl content is increased in unmodified styrene-butadiene copolymer, then low heat generation property is enhanced, but abrasion resistance is lowered
Solution Approach 1:
The conjugated diene polymer is segmented into two distinct portions: a low vinyl portion (2-20% by mol) providing abrasion resistance and a high vinyl portion (50% by mol or more) providing low heat generation property. This segmentation allows each portion to contribute its specific advantage without compromising the other, resolving the contradiction between abrasion resistance and low heat generation property.
Solution Approach 2:
Different regions of the polymer chain are assigned different vinyl content characteristics. The low vinyl portion is positioned to provide abrasion resistance where needed, while the high vinyl portion is positioned to provide low heat generation property. This local differentiation of quality within the polymer structure enables simultaneous achievement of both properties.
2Loss of energy
If expensive modifier is used to improve both abrasion resistance and low heat generation property, then both capabilities are enhanced, but manufacturing cost increases
Solution Approach 1:
Instead of using expensive chemical modifiers, the invention changes the fundamental parameter of vinyl content distribution within the polymer structure. By controlling the vinyl content in different portions of the polymer chain during polymerization, both abrasion resistance and low heat generation property are achieved through compositional parameter optimization rather than expensive additive modification.
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 rubber composition achieves both improved abrasion resistance and low heat generation properties, balancing processability and fuel efficiency in tire production.
Implementation Method 1
the high vinyl portion is in an amount of more than 0% by mol and 10% by mol or less... enhancing reactivity with silane coupling agents
Data Source
AI summary
The present invention provides a conjugated diene polymer containing a low vinyl portion having a vinyl content of 2 to 20% by mol and a high vinyl portion having a vinyl content of 50% by mol or more, and a method for producing the same; a rubber composition containing a rubber component containing the conjugated diene polymer, at least one filler selected from the group consisting of carbon black and silica, a silane coupling agent, and a crosslinking agent; crosslinked rubber prepared by crosslinking the rubber composition; and a rubber product and a tire containing the crosslinked rubber. The tire can achieve both the abrasion resistance and the low fuel consumption capability, the conjugated diene polymer, the rubber composition, and the crosslinked rubber are preferred for producing the tire, and the rubber product is excellent in abrasion resistance and low heat generation property.