Ethylene Terpolymer Crystallinity Control
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Solution Overview
Problem
Polymers rich in 1,3-diene units used in tire rubber compositions are sensitive to oxidation and can become crystalline at high ethylene content, leading to reduced rigidity and uncontrolled tire performance fluctuations due to temperature-dependent stiffness.
Innovation Solution
A terpolymer of ethylene, 1,3-diene, and an aromatic α-monoolefin with a molar ratio of ethylene units to the sum of ethylene and 1,3-diene units greater than 0.7, containing 50-80% ethylene and 10-40% aromatic α-monoolefin units, synthesized using a rare earth metallocene and organometallic compound catalytic system, which reduces crystallinity and provides a wide range of glass transition temperatures and moduli.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the molar ratio of ethylene units to the sum of ethylene and 1,3-diene units in the copolymer exceeds 0.7, then the resistance to oxidation is increased and manufacturing cost is reduced, but the copolymer becomes crystalline and experiences uncontrolled fluctuations in tire performance due to temperature-dependent rigidity changes
Solution Approach 1:
A third monomer component (aromatic α-monoolefin or cyclic olefin) is introduced as an intermediary substance to modify the copolymer structure. This intermediate component disrupts the crystalline formation of high-ethylene copolymers while maintaining oxidation resistance, thereby stabilizing rigidity across temperature variations.
Solution Approach 2:
The invention creates a ternary copolymer composite material combining ethylene, 1,3-diene, and a third monomer (aromatic α-monoolefin or cyclic olefin). This composite structure leverages the oxidation resistance of high-ethylene content while the third monomer component prevents excessive crystallinity, achieving both improved reliability and compositional stability.
2Ease of manufacture
If the proportion of ethylene in the copolymer exceeds 70 mol%, then the manufacturing cost is reduced and oxidation resistance is increased, but the crystalline parts melt at elevated temperatures causing decrease in rigidity and uncontrolled tire performance fluctuations
Solution Approach 1:
The third monomer (aromatic α-monoolefin or cyclic olefin) acts as an intermediary that prevents excessive crystallinity while allowing high ethylene content (50-80 mol%). This intermediary component ensures that the copolymer maintains stable performance characteristics during operation without the harmful effects of temperature-dependent rigidity changes.
Solution Approach 2:
The invention changes the compositional parameters by introducing a third monomer component in specific proportions (5-30 mol%). This parameter modification allows the copolymer to achieve both cost-effectiveness through high ethylene content and operational control through suppressed crystallinity, resolving the contradiction between manufacturing ease and performance control.
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 terpolymer exhibits low crystallinity, suitable glass transition temperatures, and varying rigidity, enhancing tire performance stability and oxidation resistance, making it suitable for use in tire rubber compositions.
Implementation Method 1
synthesized using a rare earth metallocene and organometallic compound catalytic system
Data Source
AI summary
The present invention concerns a terpolymer of ethylene, 1,3-diene and of an aromatic α-monoolefin in which the molar ratio between the content of ethylene units and the sum of the content of ethylene units and 1,3-diene units is greater than 0.7, said terpolymer containing more than 50 mol% to 80 mol% of ethylene units, and from 10 mol% to less than 40 mol% of aromatic α-monoolefin units, the 1,3-diene being 1,3-butadiene or isoprene. Such a diene terpolymer rich in ethylene units has the advantage of having reduced, or indeed zero, crystallinity.