Chromium Catalyst Calcination for Ethylene Polymer Properties
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Solution Overview
Problem
Current methods for manufacturing ethylene-based polymers do not adequately produce materials with high impact resistance, moldability, and a balance of stiffness and durability, particularly for applications like automotive fuel tanks, where high polymerization activity and specific physical properties are required.
Innovation Solution
A chromium catalyst is used with a specific inorganic oxide support having a high surface area and pore volume, calcined at a low temperature to achieve hexavalent chromium, allowing for ethylene homopolymerization or copolymerization with α-olefins, resulting in polymers with enhanced melt flow rate, density, molecular weight distribution, and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymerization methods are used, then production efficiency is maintained, but the polymer does not achieve high impact resistance and durability
Solution Approach 1:
The patent changes the activation temperature parameter from conventional high temperatures (400-900°C) to a low temperature (200-500°C) range. This parameter change transforms the chromium catalyst's properties to achieve high polymerization activity while producing polymers with superior impact resistance and durability, resolving the contradiction between productivity and reliability.
2Productivity
If high calcination temperature is used to activate chromium catalyst, then catalyst activity is improved, but polymer molecular weight distribution and mechanical properties deteriorate
Solution Approach 1:
The patent inverts the conventional temperature parameter by using low temperature (200-500°C) instead of high temperature for catalyst activation. This inverted parameter approach simultaneously improves catalyst activity and preserves polymer molecular weight distribution and mechanical properties, resolving the contradiction between productivity and manufacturing precision.
3Ease of manufacture
If standard chromium catalyst activation is performed, then catalyst is formed, but the polymer lacks optimal moldability and processability
Solution Approach 1:
The patent changes the activation temperature parameter to a low range (200-500°C) which simplifies the catalyst activation process while simultaneously producing polymers with excellent moldability and processability. This single parameter change resolves the contradiction between ease of manufacture and process complexity.
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 produces ethylene-based polymers with improved moldability, durability, and impact resistance, making them suitable for high-performance applications such as automotive fuel tanks with enhanced mechanical properties and stability.
Implementation Method 1
calcining for activation in a non-reducing atmosphere to thereby make at least a part of the chromium atoms hexavalent
Implementation Method 2
a chromium catalyst, which is obtained by having a chromium compound supporting on an inorganic oxide support
Data Source
AI summary
An object of the invention is to provide an ethylene-based polymer excellent in moldability and durability, and also excellent in the balance of stiffness and durability, and to provide a molded product of hollow plastic using the ethylene-based polymer. The ethylene-based polymer according to the invention is an ethylene-based polymer having specific characteristics and manufactured by a homopolymerization of ethylene or a copolymerization of ethylene and α-olefin using a chromium catalyst.