Multicomponent Copolymer Crystallinity Control for Tire Durability
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Solution Overview
Problem
Existing rubber copolymers face issues with increased crystallinity due to long chain lengths of non-conjugated olefin units, leading to impaired physical properties and workability in rubber compositions and products like tires.
Innovation Solution
A multicomponent copolymer comprising a conjugated diene unit, a non-conjugated olefin unit, and an aromatic vinyl unit, with a main chain consisting only of an acyclic structure, where the content of cis-1,4 bonds in the conjugated diene unit is 50% or more, and the non-conjugated olefin unit consists only of ethylene, reducing crystallinity and improving durability and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binary copolymer is formed by polymerizing one type of conjugated diene compound and one type of non-conjugated olefin compound to improve weather resistance, then the chain length of consecutive units derived from non-conjugated olefin compound becomes long, but crystallinity increases which damages physical properties and workability
Solution Approach 1:
The patent introduces a third monomer type (aromatic vinyl compound or another conjugated diene compound) to segment the long consecutive sequences of non-conjugated olefin units. This segmentation prevents excessive chain length of identical units, thereby reducing crystallinity while maintaining the weather resistance benefits of the non-conjugated olefin content.
Solution Approach 2:
The patent creates a ternary copolymer system combining three different monomer types (conjugated diene, non-conjugated olefin, and aromatic vinyl or additional conjugated diene). This composite polymer structure allows optimization of multiple properties simultaneously: weather resistance from non-conjugated olefin units, while controlling crystallinity through the interrupting effect of the third monomer type.
2Reliability
If the chain length of consecutive units derived from non-conjugated olefin compound is increased to improve weather resistance, then weather resistance improves, but crystallinity increases which impairs physical properties as elastomer
Solution Approach 1:
By introducing a third monomer type into the copolymer chain, the patent segments the consecutive sequences of non-conjugated olefin units. This prevents the formation of long crystalline regions while preserving enough non-conjugated olefin content to maintain weather resistance, thereby protecting the elastomeric physical properties.
Solution Approach 2:
The patent optimizes the compositional parameters by specifying precise ranges for each monomer content and the sequence distribution parameter (X value). By controlling these parameters, the patent achieves a balance where weather resistance is improved through non-conjugated olefin units while crystallinity is suppressed through the presence and distribution of the third monomer type.
Data Source
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AI summary
Provided is a polymer that contributes to the improvement of the durability and weather resistance of rubber compositions or rubber products such as a tire, and has low crystallinity. Disclosed is a multicomponent copolymer comprising a conjugated diene unit, a non-conjugated olefin unit, and an aromatic vinyl unit, wherein the multicomponent copolymer has a main chain consisting only of an acyclic structure, and the content of cis-1,4 bonds in the entire conjugated diene unit is 50% or more.