Polypropylene Melt-blown Web Peroxide Visbreaking
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Solution Overview
Problem
Existing melt-blown webs made from polypropylene struggle to achieve a balance between high hydrostatic head and low air permeability, which are essential properties for various industrial and hygiene applications.
Innovation Solution
A melt-blown web is produced using a propylene-based polymer that is melt-mixed with two peroxides having different half-life temperatures. This process involves initial visbreaking at lower temperatures followed by further processing at higher temperatures to create fibers with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If polypropylene with high melt flow index is used to make melt-blown webs, then air permeability is improved, but hydrostatic head deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the polypropylene by incorporating specific additives (ethylene-propylene-diene copolymer, peroxides, and inorganic fillers) to modify the polymer's rheological properties and fiber formation characteristics, achieving a balance between air permeability and hydrostatic head
Solution Approach 2:
The invention creates a composite polypropylene material by combining base polypropylene with ethylene-propylene-diene copolymer, peroxides, and inorganic fillers, resulting in a composite material that simultaneously achieves desirable air permeability and hydrostatic head properties
2Ease of manufacture
If polypropylene with high melt flow index is used to make melt-blown webs, then processing ease is improved, but liquid barrier performance deteriorates
Solution Approach 1:
The invention modifies the polypropylene's processing parameters and chemical composition to achieve optimal melt characteristics during fiber formation while maintaining liquid barrier performance in the final product
Solution Approach 2:
The composite material formulation with specific copolymer and filler combinations enables both ease of processing during melt-blown fabrication and effective liquid barrier performance in the finished web
3Productivity
If viscosity reduction is performed using peroxides or hydroxylamine ester, then melt flow index is improved, but material purity deteriorates
Solution Approach 1:
The invention changes the chemical approach to viscosity reduction by using a combination of peroxides and inorganic fillers that achieve the desired melt flow index while minimizing degradation and maintaining material purity
Solution Approach 2:
The use of inorganic fillers serves as a cost-effective alternative to extensive material purification processes, achieving the desired rheological properties without requiring high-purity base materials
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 resulting melt-blown web exhibits superior hydrostatic head and low air permeability, outperforming webs made from polypropylene with high melt flow index, thus meeting the demands of diverse applications.
Implementation Method 1
the first peroxide has a half-life time of 1 hour at a first temperature T1/2 1 and the second peroxide has a half-life time of 1 hour at a second temperature T1/2 2
Implementation Method 2
initial visbreaking at lower temperatures followed by further processing at higher temperatures
Implementation Method 3
processing the composition obtained by step a) by a melt-blown process at temperatures between 240 oC and 300 oC
Implementation Method 4
a melt-blown web is produced using a propylene-based polymer that is melt-mixed with two peroxides
Data Source
AI summary
The invention relates to a melt-blown web comprising melt-blown fibers obtained by a) melt-mixing a propylene-based polymer, a first peroxide and a second peroxide at temperatures between 180 ºC and 240 ºC, preferably between 200 ºC and 220 ºC, wherein the first peroxide has a half-life time of 1 hour at a first temperature T1/21 and the second peroxide has a half-life time of 1 hour at a second temperature T1/22, wherein T1/22 is higher than T1/21 and b) processing the composition obtained by step a) by a melt-blown process at temperatures between 240 ºC and 300 ºC, preferably between 245 ºC and 280 ºC, to provide the melt-blown fibers.