Ethylene–α-Olefin–Polyene Copolymers via Bridged Metallocene Catalysts
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Solution Overview
Problem
Conventional methods for manufacturing ethylene/α-olefin/non-conjugated polyene copolymers face challenges in achieving high molecular weight, high non-conjugated polyene copolymerization performance, and high polymerization activity simultaneously, particularly during high-temperature polymerization, leading to increased production costs and residual catalyst residues.
Innovation Solution
A method using a bridged metallocene compound with a specific fluorene structure as a catalyst for copolymerizing ethylene, α-olefin, and non-conjugated polyene, achieving a molar ratio of ethylene to α-olefin, non-conjugated polyene content, and a B value to enhance molecular weight and copolymerization performance while maintaining high polymerization activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Ziegler-Natta catalyst system is used for copolymerization, then the copolymer exhibits excellent heat aging resistance and weather resistance, but the polymerization activity is low and catalyst life is short
Solution Approach 1:
The patent employs a metallocene catalyst with a specific ligand structure (Formula 1) that changes the chemical parameters of the catalyst system. This metallocene catalyst exhibits high polymerization activity while maintaining the ability to produce copolymers with excellent heat aging resistance, thereby resolving the contradiction between reliability and productivity.
2Strength
If polymerization is conducted at low temperatures (0 to 50°C) to maintain catalyst activity, then the copolymer molecular weight increases, but the polymerization solution viscosity becomes high and productivity decreases
Solution Approach 1:
The metallocene catalyst enables polymerization at elevated temperatures (50-100°C) while maintaining high molecular weight copolymers. The specific ligand structure in Formula 1 allows the catalyst to function effectively at these higher temperatures, reducing solution viscosity and improving productivity without sacrificing molecular weight.
3Productivity
If the polymerization temperature is increased to reduce polymerization solution viscosity, then productivity improves, but the copolymer molecular weight decreases
Solution Approach 1:
The metallocene catalyst with the specific ligand structure in Formula 1 is designed to maintain high activity at elevated temperatures (50-100°C). This allows the polymerization to be conducted at higher temperatures that reduce solution viscosity and improve productivity, while the catalyst's stable structure ensures that copolymer molecular weight remains high.
4Productivity
If a high polymerization activity catalyst is used to increase productivity, then less catalyst residue remains in the copolymer, but the non-conjugated polyene copolymerization performance decreases
Solution Approach 1:
The metallocene catalyst with the specific ligand structure in Formula 1 is designed with electron-donating groups that enhance both polymerization activity and non-conjugated polyene copolymerization performance. The ligand structure parameters are optimized to achieve high activity while maintaining the ability to incorporate non-conjugated polyene units effectively.
5Ease of manufacture
If the amount of unreacted non-conjugated polyene in the polymerization solution is reduced, then the load of heating and pressure reduction operations decreases, but the copolymerization performance requirements increase
Solution Approach 1:
The metallocene catalyst with the specific ligand structure in Formula 1 is designed to enhance non-conjugated polyene copolymerization performance, allowing for more complete incorporation of non-conjugated polyene units into the copolymer chain. This reduces the amount of unreacted non-conjugated polyene in the polymerization solution, thereby decreasing the load of post-polymerization processing operations.
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 method enables the production of ethylene/α-olefin/non-conjugated polyene copolymers with high molecular weight, reduced residual non-conjugated polyene, and lower catalyst costs, enhancing productivity and reducing post-polymerization process loads, resulting in cost-effective and high-performance materials.
Implementation Method 1
a method using a bridged metallocene compound with a specific fluorene structure as a catalyst for copolymerizing ethylene, α-olefin, and non-conjugated polyene
Data Source
Figure 1
AI summary
The purpose of the present invention is to obtain an ethylene·α-olefin·non-conjugated polyene copolymer that has a low permanent compression set at low temperatures, is flexible, and has an excellent balance of rubber elasticity at low temperatures and tensile strength at normal temperatures. This ethylene-based polymer is an ethylene·α-olefin·non-conjugated polyene copolymer that includes units derived from ethylene (A), units derived from an α-olefin (B) containing 4-20 carbon atoms, and units derived from a non-conjugated polyene (C) and satisfies (1)-(4). (1) The molar ratio of (A) to (B) is 40/60-90/10, (2) the contained amount of the units derived from (C) is 0.1-6.0 mol%, (3) ML(1+4)125°C is 5-100, and (4) the B value is 1.20 or more.