Metallocene Catalysts for 1-Butene Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for polymerizing 1-butene result in polymers with unsatisfactory mechanical properties and high catalyst residue content, leading to suboptimal properties and the need for additional processing steps.
Innovation Solution
A process using a catalyst system comprising a bridged metallocene compound with a substituted-indenyl ligand, alumoxane, and an organo-aluminum compound to polymerize 1-butene, which achieves high yield and balances elastic modulus and melting point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TiCl3 based catalyst components with DEAC are used for polymerizing 1-butene, then the polymerization can proceed, but the mechanical properties of the obtained polymers are unsatisfactory and catalyst residue content is high
Solution Approach 1:
The patent changes the catalyst system parameters from TiCl3/DEAC to metallocene compounds with specific ligand configurations (Cp2ZrCl2, Cp2HfCl2, etc.) and controlled sterically hindered ligands, achieving both high productivity and improved mechanical properties simultaneously
Solution Approach 2:
The patent employs composite catalyst systems combining metallocene compounds with specific ligands (such as indenyl, fluorenyl, or substituted cyclopentadienyl ligands) to create a synergistic effect that improves both polymerization efficiency and polymer quality
2Productivity
If TiCl3 based catalysts are used for polymerizing 1-butene, then polymerization can occur, but the yield is low and catalyst residue content is high requiring deashing steps
Solution Approach 1:
The patent extracts and eliminates the need for deashing steps by using metallocene catalysts that leave minimal or no catalyst residues, thereby simplifying the overall process while maintaining high yield
Solution Approach 2:
The patent changes the catalyst residue profile from high Ti content with TiCl3/DEAC systems to minimal or no residues with metallocene systems, eliminating the need for subsequent deashing processing steps
3Productivity
If conventional metallocene compounds are used to produce 1-butene polymers, then high yield and isotacticity are achieved, but the elastic modulus is too high and melting point is too high for flexible applications
Solution Approach 1:
The patent introduces sterically hindered ligands at specific positions on the metallocene compound (such as ortho-substituted cyclopentadienyl ligands or indenyl ligands) to locally modify the catalytic activity and polymer microstructure, achieving lower elastic modulus while maintaining high yield and isotacticity
Solution Approach 2:
The patent changes the steric parameters of the metallocene ligands (using bulky groups like t-butyl, isopropyl, or indenyl substituents) to control the polymer microstructure and physical properties, achieving the desired balance between yield, isotacticity, elastic modulus, and melting point
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 process produces 1-butene polymers with low elastic modulus, high molecular weight, and improved mechanical properties, reducing the need for subsequent deashing steps and enhancing polymer performance.
Implementation Method 1
polymerizing 1-butene and optionally ethylene, propylene or said alpha-olefin, in the presence of a catalyst system obtainable by contacting: a) at least a metallocene compound of formula (I)
Data Source
AI summary
A process for preparing 1-butene polymers comprising polymerizing 1-butene and optionally ethylene, propylene or higher alpha-olefin, in the presence of a catalyst system obtainable by contacting:a) metallocene compound of formula (I):wherein: M is a transition metal; p is an integer from 0 to 3; X, same or different, is a hydrogen atom, a halogen atom, or a hydrocarbon group; L is a divalent C1-C40 hydrocarbon radical; R1 is a C1-C40 hydrocarbon radical; T1, is a moiety of formula (IIa) or (IIb):wherein R2 and R3, are C1-C40 hydrocarbon radicals or they can form together a C3-C7-membered ring; R4 is C1-C40 hydrocarbon radicals; T2 and T3, are a moiety of formula (IIIa) or (IIIb):wherein R6 and R7, equal to or different from each other, are hydrogen atoms or C1-C40 hydrocarbon radicals; R5 is a hydrogen atom or a C1-C40 hydrocarbon radicals; with the proviso that if T1 is a moiety of formula (IIa) at least one between T2 and T3 is a moiety of formula (IIIb), and if T1 is a moiety of formula (IIb) at least one between T2 and T3 is a moiety of formula (IIIa); andb) at least an alumoxane or a compound able to form an alkylmetallocene cation.