Multi-component copolymer reduces crystallinity in rubber
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Solution Overview
Problem
Conventional rubber copolymers with high cis-1,4 bond content in conjugated diene units lead to increased crystallinity and poor rollability, limiting their application in rubber articles such as tires and conveyor belts.
Innovation Solution
A multi-component copolymer comprising conjugated diene units, non-conjugated olefin units, and aromatic vinyl units, with a specific ratio of aromatic vinyl units less than 50% in amorphous parts, to reduce crystallinity and improve rollability while maintaining low heat generation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a copolymer with high cis-1,4 bond content in conjugated diene units is used, then low heat generating property is improved, but crystallinity increases and rollability deteriorates
Solution Approach 1:
The copolymer is segmented into three distinct types of units (conjugated diene, non-conjugated olefin, and aromatic vinyl) with specific structural characteristics. Each unit type contributes different properties: conjugated diene units provide low heat generation through high cis-1,4 bonds, while non-conjugated olefin and aromatic vinyl units disrupt crystal formation to maintain rollability. This segmentation allows independent optimization of each unit's function.
Solution Approach 2:
The patent applies local quality by specifying that aromatic vinyl units should constitute less than 50% of all aromatic vinyl units in the copolymer structure. This localized control of aromatic vinyl content ensures that the copolymer maintains sufficient rollability while still benefiting from the low heat generation properties of high cis-1,4 bond content conjugated diene units.
2Reliability
If a bicopolymer of one conjugated diene compound and one non-conjugated olefin compound is used, then durability is improved, but chain length of continuous non-conjugated olefin units increases resulting in increased crystallinity
Solution Approach 1:
The patent segments the copolymer into three unit types instead of two, introducing aromatic vinyl units as a third component. This segmentation interrupts the continuous sequences of non-conjugated olefin units that would otherwise form long crystalline regions. The aromatic vinyl units act as spacers that break up the regularity required for crystallization while preserving the durability benefits of the conjugated diene and non-conjugated olefin units.
Data Source
AI summary
Provided is a multi-component copolymer capable of improving the rollability of a rubber composition while having excellent low heat generating property. The multi-component copolymer comprises conjugated diene units, non-conjugated olefin units and aromatic vinyl units, wherein: a ratio among all of the aromatic vinyl units of at least one aromatic vinyl unit existing in amorphous parts inclusive of the conjugated diene units is less than 50%.