Polyolefin Powder Particle Size Distribution Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polyolefin polymer powders with high proportions of large particles lead to issues like gel formation and white spots in final products such as films and pipes, affecting homogeneity and physical properties, despite efforts to reduce fines content.
Innovation Solution
A multimodal polyethylene powder with a specific particle size distribution, characterized by D95 < 355µm, D5 ≥ 60µm, and a span (D90-D10)/D50 < 1.2, produced using a catalyst system involving magnesium, titanium or zirconium, and a halogen-containing aluminic compound, is used to minimize large particles and maintain low fines content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst system with high productivity is used, then the proportion of large particles is reduced, but the fines content increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling catalyst components (Ti, Al, Mg ratios), preparation conditions (temperature, time, solvents), and particle size distribution parameters (D95 < 355μm, span < 1.2) to achieve the optimal balance between productivity and fines content in the polymer powder
2Object-affected harmful factors
If the proportion of large particles is reduced, then gel formation and white spots are reduced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by controlling the particle size distribution at the catalyst preparation stage and polymerization stage, ensuring that the polymer powder already has the desired D95 < 355μm and span < 1.2 characteristics before compounding, thereby preventing gel formation and white spots in the final product without requiring complex post-processing
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
This approach reduces gel counts and white spots in blown films and pipes, allowing for lower specific energy in pelletization and enhanced bulk densities, while maintaining low fines content, resulting in more homogeneous products with improved physical properties.
Implementation Method 1
a catalyst system comprising: (a) a catalytic solid which comprises magnesium, at least one transition metal selected from the group consisting of titanium and zirconium, and a halogen
Data Source
Figure 1
Figure 2
AI summary
An uncompounded polyolefin powder is disclosed, having a particle size distribution such that D95 is less than 355μm and (D90-D10)/D50 is less than 1.2, where D95, D90, D50 and D10 are defined such that 95vol%, 90vol%, 50vol% or 10vol% of the polymer particles have a diameter of less than D95, D90, D50 and D10 respectively. A process for making the powder is also disclosed.