Synergistic Peroxide and Hydroxylamine Ester Visbreaking
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Solution Overview
Problem
Current visbreaking processes for polypropylene polymers require high temperatures (above 280°C) or multiple extrusion steps to achieve efficient molecular weight reduction and narrow molecular weight distribution, which limits their application in producing controlled rheology polypropylene grades with improved barrier properties at lower melt extrusion temperatures.
Innovation Solution
A synergistic composition of peroxide and hydroxylamine ester, specifically in the range of 30wt%:70wt% to 85wt%:15wt%, is added to polypropylene polymers at melt extrusion temperatures below 250°C to enhance visbreaking efficiency, using sterically hindered amine derivatives and peroxides like 2,5-dimethyl-2,5-bis(tert.butyl-peroxy)hexane, dicumyl-peroxide, and hydroxylamine esters like Irgatec CR76, to increase melt flow rate and reduce molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperatures (above 280°C) are used for visbreaking, then molecular weight reduction efficiency is improved, but processing cost and energy consumption increase
Solution Approach 1:
The patent changes the chemical parameters by introducing a synergistic combination of peroxide and hydroxylamine ester additives that modify the degradation mechanism, enabling effective visbreaking at lower temperatures (below 250°C) without requiring high thermal energy input
Solution Approach 2:
The patent uses peroxide and hydroxylamine ester as intermediary substances that facilitate molecular weight reduction through chemical catalysis, replacing the need for high thermal energy and enabling the process to proceed at lower temperatures
2Manufacturing precision
If multiple extrusion steps are used to achieve narrow molecular weight distribution, then product quality is improved, but process complexity and production time increase
Solution Approach 1:
The patent merges the functions of multiple extrusion steps into a single extrusion process by using a synergistic additive system that simultaneously achieves molecular weight reduction and narrow molecular weight distribution in one pass, eliminating the need for sequential processing steps
Solution Approach 2:
The patent employs a composite additive system combining peroxide and hydroxylamine ester in specific ratios, where the synergistic interaction between components enables complex molecular weight control functions that would otherwise require multiple processing steps
3Quantity of substance
If peroxide is used alone for visbreaking, then molecular weight reduction is achieved, but molecular weight distribution remains broad
Solution Approach 1:
The patent changes the chemical composition parameters by adding hydroxylamine ester to the peroxide system, creating a synergistic effect that modifies the degradation kinetics to produce both molecular weight reduction and narrowing of the molecular weight distribution
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 combination of peroxide and hydroxylamine ester significantly enhances visbreaking efficiency, allowing for the production of polypropylene grades with improved barrier properties and reduced molecular weight at lower temperatures, achieving higher molecular weight reduction than expected from individual components, thus enabling more economical processing and improved continuity in fiber spinning.
Implementation Method 1
Under the given processing conditions, the peroxide disintegrates into free radicals, which initiate the chain cleavage reactions
Implementation Method 2
the peroxide disintegrates into free radicals, which initiate the chain cleavage reactions and form polymers having the desired rheological properties
Implementation Method 3
Known degradation processes proceed either thermally, in particular at temperatures above 280°C, or in the presence of free-radical generators
Data Source
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Figure 3~4
AI summary
Synergistic visbreaking composition of peroxide and a hydroxylamine ester for increasing the visbreaking efficiency for polypropylene polymers at melt extrusion temperatures below 250°C and its use in visbreaking polypropylene. The present invention is furthermore related to the use of such visbroken polypropylene polymers for producing melt blown non-wovens with improved barrier properties