Bimodal Polypropylene Melt-Blown Web for Hydrohead and Air Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current melt-blown polypropylene webs in the hygiene and filtration industries face challenges in achieving high hydrohead (barrier properties) while maintaining low air permeability, which is essential for reducing material consumption and costs, and CO2 footprint.
Innovation Solution
A melt-blown fiber composition comprising two polypropylenes with different molecular weights and melt flow rates, where the first polypropylene has a weight molecular weight of at most 45 kg/mol and the second polypropylene has a weight molecular weight in the range of 50 to 120 kg/mol, with a melt flow rate between 400 to 3,500 g/10 min, optimized to achieve high hydrohead and low air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high hydrohead is achieved through increased web weight, then barrier properties improve, but material consumption and costs increase
Solution Approach 1:
The patent changes the molecular weight parameters of the polypropylene components, using a bimodal distribution with specific weight average molecular weights (Mw) ranges: first polypropylene with Mw of 50-150 kg/mol and second polypropylene with Mw of 10-45 kg/mol. This parameter optimization enables high barrier properties at reduced web weights
Solution Approach 2:
The patent creates a composite polypropylene system by combining two different polypropylene types with distinct molecular weight characteristics. The first polypropylene provides structural integrity while the second enhances barrier properties, achieving synergistic effects that reduce overall material consumption while maintaining or improving barrier performance
2Quantity of substance
If web weight is reduced to lower material consumption, then costs decrease, but barrier properties deteriorate
Solution Approach 1:
The patent optimizes the molecular weight parameters by specifying precise ranges: first polypropylene with Mw of 50-150 kg/mol and second polypropylene with Mw of 10-45 kg/mol. This parameter control ensures that even at reduced web weights, the barrier properties are maintained through enhanced molecular-level packing and reduced free volume
Solution Approach 2:
The patent applies local quality by having different polypropylene components perform different functions within the same web structure. The lower molecular weight polypropylene specifically targets barrier enhancement at the molecular level, while the higher molecular weight component provides structural support, allowing localized optimization of barrier properties without increasing overall web weight
3Reliability
If air permeability is reduced to improve barrier properties, then hydrohead increases, but web weight must increase
Solution Approach 1:
The patent changes the molecular weight parameters to achieve ultra-low air permeability without increasing web weight. The specific Mw ranges (first PP: 50-150 kg/mol, second PP: 10-45 kg/mol) create a dense fiber matrix with reduced inter-fiber voids, achieving air permeability below 100 mL/min while maintaining low web weights
Solution Approach 2:
The composite polypropylene system creates a synergistic structure where the two different molecular weight components form a denser, more interlocked fiber network. This composite structure reduces air permeability more effectively than single-component systems, achieving high hydrohead values without proportionally increasing web weight
Data Source
AI summary
Melt-blown fiber comprising two polypropylenes which differ in their molecular weight.