Metallocene Olefin Polymer Tensile Strength

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Solution Overview

Problem

Low-density olefin-based polymers face challenges in achieving high tensile strength due to limitations in molecular weight and compatibility with polar resins and metals, with existing methods resulting in poor miscibility and appearance characteristics.

Innovation Solution

A low-density olefin-based polymer with a density range of 0.85 to 0.90 g/cc, melt index of 0.1 to 15 g/10 min, molecular weight distribution of 1.0 to 3.0, and specific molecular weight ratios, achieved through continuous solution polymerization using a metallocene catalyst composition with transition metal compounds, enhancing foamability and tensile strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If radical polymerization grafting of polar group-containing monomer onto polyolefin is used to increase affinity for polar materials, then compatibility with polar resins is improved, but cross-linking and molecular chain cleavage occur causing poor viscosity balance and low miscibility

Engineering Contradiction:

Improvecompatibility with polar resinsVSAvoidmolecular chain integrity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent changes the fundamental parameter of polymerization mechanism from radical polymerization to coordination polymerization using metallocene catalyst. This parameter change allows incorporation of polar monomers (like vinyl alcohol, acrylic acid, itaconic acid) into the polyolefin chain without causing cross-linking or chain cleavage, achieving both compatibility with polar resins and molecular chain stability simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the radical polymerization mechanism with a coordination polymerization mechanism using metallocene catalyst. This substitution eliminates the harmful side reactions (cross-linking and chain scission) characteristic of radical polymerization while maintaining the ability to graft polar groups onto the polyolefin backbone

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If metal catalysts such as titanium or vanadium catalysts are used for copolymerization of polar monomers, then olefin polymer can be prepared, but molecular weight distribution becomes wide and polymerization activity is low

Engineering Contradiction:

Improvepolymer preparation capabilityVSAvoidpolymerization activity

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the catalyst system parameter from conventional metal catalysts (titanium, vanadium) to metallocene catalysts. This parameter change simultaneously improves polymerization activity and produces polymers with narrow molecular weight distribution, while maintaining the capability to copolymerize polar monomers with olefins

Inventive Principle:

Principle #35Parameter changes

3Productivity

If metallocene catalyst with non-crosslinked cyclopentadienyl group is used to prepare polyolefin with polar group, then polymerization activity is high, but polymerization activity becomes very low requiring complicated protecting group removal

Engineering Contradiction:

Improvepolymerization activityVSAvoidprocess complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by using ansa-substituted metallocene catalysts with specific ligand structures (indene, fluorene, cyclopentadiene rings connected by bridging groups). These localized structural modifications to the catalyst create chiral environments that enable high polymerization activity while incorporating polar monomers directly without requiring protecting groups, thus avoiding process complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ansa-metallocene catalyst acts as an intermediary that facilitates the copolymerization of polar monomers with olefins. The specific ligand structure of the catalyst mediates the reaction to proceed with high activity without requiring protecting groups on the polar monomers, eliminating the need for additional protection and deprotection steps

Inventive Principle:

Principle #24Intermediary (Mediator)

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 polymer exhibits improved tensile strength and foamability while maintaining low density, with superior mechanical properties and moldability, suitable for diverse applications including blow molding and injection molding.

Implementation Method 1

continuous solution polymerization using a metallocene catalyst composition with transition metal compounds

Methodology Applied

Scientific EffectCoordination polymerization: Catalysis

Data Source

PatentUS11440984B2Olefin-based polymer

Publication Date: 2022.09.13 LG CHEM LTD

AI summary

The present invention relates to an olefin-based polymer, which has (1) a density (d) ranging from 0.85 to 0.90 g/cc, (2) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 0.1 g/10 min to 15 g/10 min, (3) a molecular weight distribution (MWD) in a range of 1.0 to 3.0, and (4) a number average molecular weight (Mn) and a Z+1 average molecular weight (Mz+1) satisfying the Equation 1, {Mn/(Mz+1)}×100>15. The olefin-based polymer according to the present invention is a low-density olefin-based polymer and exhibits excellent tensile strength due to having improved molecular weight as compared to the flow index.