Metallocene Copolymer for Ozone and Crack Resistance
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Solution Overview
Problem
Existing methods for copolymerizing conjugated dienes and non-conjugated olefins using Ziegler-Natta catalysts struggle to achieve high cis-1,4 bond content and sufficient non-conjugated olefin content, which limits the ozone resistance and crack growth resistance of rubber compositions.
Innovation Solution
A conjugated diene/non-conjugated olefin copolymer is developed with a cis-1,4 bond content of 50% or more and a non-conjugated olefin content of 20 mol% or more, using specific catalysts such as metallocene complexes and half metallocene cation complexes, to enhance the properties of the rubber composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Ziegler-Natta catalyst systems are used for copolymerization of conjugated dienes and non-conjugated olefins, then homopolymerization is achieved, but efficient copolymerization cannot be provided
Solution Approach 1:
The patent changes the catalyst system parameters from conventional Ziegler-Natta catalysts to metallocene complex catalysts combined with specific co-catalysts. This parameter change enables efficient copolymerization of conjugated dienes and non-conjugated olefins while maintaining control over polymer structure and composition, directly resolving the contradiction between copolymerization efficiency and capability
Solution Approach 2:
The patent employs a composite catalyst system consisting of metallocene complex catalysts and specific co-catalysts (organometallic compounds). This composite approach creates a synergistic effect that enables efficient copolymerization while providing control over the incorporation of non-conjugated olefins into the polymer chain
2Object-affected harmful factors
If non-conjugated olefin content is increased to improve ozone resistance, then double bonds in conjugated diene units decrease, but crack growth resistance deteriorates
Solution Approach 1:
The patent optimizes the non-conjugated olefin content parameter to a specific range (20-60 mol%) where both ozone resistance and crack growth resistance are improved. This parameter optimization resolves the contradiction by finding the optimal balance point rather than simply increasing or decreasing the olefin content
Solution Approach 2:
The patent controls the microstructure of the polymer by ensuring high cis-1,4 bond content (50% or more) in the conjugated diene units while simultaneously incorporating non-conjugated olefins. This local structural control allows different regions of the polymer to provide different functions: cis-1,4 bonds provide crack resistance while non-conjugated olefins provide ozone resistance
3Strength
If cis-1,4 bond content is increased to improve crack growth resistance, then polymer structure becomes more constrained, but elongation-induced crystallization ability may deteriorate
Solution Approach 1:
The patent optimizes the cis-1,4 bond content parameter to be 50% or more, which provides sufficient crack growth resistance while maintaining enough chain flexibility for elongation-induced crystallization. This parameter optimization resolves the contradiction by avoiding excessive cis-1,4 content that would overly constrain the polymer chains
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 copolymer improves weather resistance, ozone resistance, and crack resistance while maintaining high elongation-induced crystallization ability and low glass transition temperature, suitable for applications like tire tread rubber.
Implementation Method 1
coordination anionic polymerization using catalyst systems represented by a Ziegler-Natta catalyst allows for homopolymerization of olefins and dienes
Data Source
AI summary
The present invention provides a copolymer of a conjugated diene compound and a non-conjugated olefin, in which the conjugated diene unit has cis-1,4 bonds and the non-conjugated olefin contains many ethylene structures. In a copolymer of a conjugated diene compound and an unconjugated olefin other than the conjugated diene compound, the conjugated diene unit has a cis-1,4 bond content of 50 % or more and the unconjugated olefin is contained in an amount of 20 mol% or more.