Ethylene interpolymer products having unique melt flow-intrinsic viscosity (MFIVI) and low unsaturation
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Solution Overview
Problem
Existing solution polymerization processes face challenges in achieving higher production rates, increasing molecular weight of ethylene interpolymers at high reactor temperatures, efficiently incorporating α-olefins, and producing ethylene interpolymers with desirable properties for end-use applications such as packaging films.
Innovation Solution
Employing a bridged metallocene catalyst formulation in a continuous solution polymerization process with specific ethylene and α-olefin ratios, utilizing a process solvent in multiple reactors, and optimizing reactor conditions to produce ethylene interpolymers with controlled molecular weight, unsaturation, and residual catalytic metal content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reactor temperature is decreased to increase molecular weight, then molecular weight increases, but solution viscosity becomes too high
Solution Approach 1:
The patent employs a bridged metallocene catalyst formulation that fundamentally changes the kinetic parameters of the polymerization reaction, enabling high molecular weight production at elevated temperatures where conventional catalysts would produce excessively viscous solutions. The catalyst's unique structure allows maintaining low solution viscosity while achieving high molecular weight through enhanced catalytic activity and controlled polymerization kinetics.
2Productivity
If conventional catalyst formulations are used, then production rates are limited, but increasing production rates compromises polymer properties
Solution Approach 1:
The bridged metallocene catalyst formulation introduces new kinetic parameters that decouple production rate from polymer quality. The catalyst system achieves ultra-high activity levels while maintaining precise control over molecular weight, comonomer incorporation, and polymer architecture, allowing simultaneous optimization of both productivity and polymer properties.
Solution Approach 2:
The patent utilizes a composite catalyst system comprising bridged metallocene complex, alumoxane co-catalyst, and ionic activator. This composite formulation synergistically combines multiple components to achieve both high production rates and superior polymer properties, with each component contributing specific functions that collectively resolve the productivity-quality trade-off.
3Stability of the object's composition
If higher amounts of α-olefin are used to achieve desired copolymer composition, then copolymer composition is achieved, but α-olefin consumption increases and reactor efficiency decreases
Solution Approach 1:
The bridged metallocene catalyst exhibits dramatically enhanced comonomer incorporation efficiency, achieving the same copolymer composition with significantly lower α-olefin feed requirements. The catalyst's electronic and steric parameters are optimized to favor selective monomer insertion, reducing waste of expensive comonomers while maintaining desired copolymer composition.
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 achieves a 10% increase in production rate, reduces α-olefin usage, and enhances film properties like optical properties and hot tack performance, resulting in ethylene interpolymers suitable for packaging films.
Implementation Method 1
The catalyst formulations and solution process disclosed herein, produce unique ethylene interpolymer products that have desirable properties in a variety of end-use applications
Implementation Method 2
One embodiment of a suitable homogeneous catalyst formulation is a bridged metallocene catalyst formulation comprising a component A defined by Formula (I)
Implementation Method 3
polymerizing ethylene and optionally at least one α-olefin, in a process solvent, in one or more reactors using a bridged metallocene catalyst to form the ethylene interpolymer product
Data Source
AI summary
This disclosure relates to ethylene interpolymer products comprising a Melt Flow-Intrinsic Viscosity Index value, MFIVI, from ≥0.05 to ≤0.80; a first derivative of a melt flow distribution function, formula (I) at a loading of 4000 g, from >−1.51 to ≤−1.15; a sum of unsaturation, SUMU, from ≥0.005 to <0.047 unsaturations per 100 carbon atoms; and a residual catalytic metal from ≥0.03 to ≤5 ppm of hafnium. Ethylene interpolymer products comprise at least two ethylene interpolymers. Ethylene interpolymer products are characterized by a melt index (I2) from 0.3 to 500 dg/minute, a density from 0.855 to 0.975 g/cc and from 0 to 25 mole percent of one or more a-olefins. Ethylene interpolymer products have polydispersity, Mw/Mn, from 1.7 to 25; and CDBI50 values from 1% to 98%. These ethylene interpolymer products have utility in flexible as well as rigid applications.dLog(1/In)dLog(loading)(I)