Polypropylene Fiber Heat Resistance and Adhesion via Isotactic Pentad Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polypropylene fibers face challenges in heat resistance, hydrophilicity, and compatibility with matrices, particularly in high-temperature applications and hydraulic products, where they exhibit reduced strength and adhesion, leading to inadequate performance in ropes, sheets, and composite materials.
Innovation Solution
A polypropylene fiber with an isotactic pentad fraction of 94% or more, exhibiting a uniform crystal structure, high heat resistance, and specific surface irregularities, is produced through melt spinning, pre-drawing, and post-drawing processes, enhancing its strength, water retentivity, and compatibility with hydraulic substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polypropylene fiber is used for high-temperature applications, then heat resistance is required, but the fiber exhibits reduced strength and adhesion at elevated temperatures
Solution Approach 1:
The invention changes the chemical composition parameters of polypropylene by specifying an isotactic pentad fraction of 96% or more and controlling the melt flow rate within 0.1 to 30 g/10 minutes. These parameter changes result in a uniform crystal structure with a single endothermic peak in DSC measurement, achieving both heat resistance (maintaining dimensional stability at high temperatures) and fiber strength (retaining mechanical properties at elevated temperatures up to 150°C or higher)
2Strength
If polypropylene fiber is used as reinforcement material, then adhesion to matrix is required, but the fiber exhibits poor hydrophilicity and insufficient adhesion
Solution Approach 1:
The invention changes the molecular structure parameters of polypropylene by specifying an isotactic pentad fraction of 96% or more, which creates a uniform crystal structure. This structural change improves hydrophilicity and adhesion to matrices (such as hydraulic substances like cement) while maintaining the inherent advantages of polypropylene fiber, enabling effective use as reinforcement material in composite materials
3Ease of manufacture
If conventional polypropylene fiber production method is used, then manufacturing simplicity is maintained, but the crystal structure is non-uniform and heat resistance is insufficient
Solution Approach 1:
The invention changes the resin selection parameters by specifying polypropylene with an isotactic pentad fraction of 96% or more and controlled melt flow rate (0.1 to 30 g/10 minutes). These parameter changes achieve a uniform crystal structure with a single endothermic peak, providing sufficient heat resistance while maintaining ease of manufacture through standard melt spinning and drawing processes without requiring complex additional steps
4Adaptability or versatility
If polypropylene fiber is used in hydraulic products, then compatibility with hydraulic substances is required, but the fiber exhibits insufficient compatibility and adhesion
Solution Approach 1:
The invention changes the chemical structure parameters of polypropylene by specifying an isotactic pentad fraction of 96% or more, which creates a uniform crystal structure with improved hydrophilicity. This enables better compatibility with hydraulic substances (such as cement matrices) and sufficient adhesion, allowing the fiber to be effectively used as reinforcement in hydraulic products while maintaining structural integrity
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 polypropylene fibers demonstrate improved heat resistance, strength, and water retentivity, maintaining high mechanical properties even at elevated temperatures, and exhibit excellent adhesion with matrices, leading to enhanced performance in ropes, sheets, and composite materials.
Implementation Method 1
subjecting polypropylene having an isotactic pentad fraction (IPF) of 94% or more to melt spinning
Implementation Method 2
cooling the resultant to solidify to thereby produce a polypropylene undrawn fiber, and then subjecting the resulting polypropylene undrawn fiber to pre-drawing and post-drawing under specific conditions
Data Source
AI summary
The present invention aims to provide a polypropylene fiber (PP fiber) excellent in strength, heat resistance, and water-absorption properties, a method of producing the same, and a hydraulic composition, a rope, a sheet-shaped fiber structure, and a composite material with an organic polymer each using the PP fiber. The present invention provides: a PP fiber having a fiber having a fiber strength of 7 cN/dtex or more and having either or both of (i) DSC properties such that the endothermic peak shape by DSC is a single shape having a half width of 10° C. or lower and the melt enthalpy change (AH) is 125 J/ g and (ii) irregular properties such that the single fiber fineness is 0.i to 3 dtex and irregularities are formed on the surface.