Bicomponent Fiber Sheath Adhesion via Maleic Anhydride Grafting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bicomponent fibers with a core-sheath structure, particularly those with a polyethylene terephthalate (PET) core and a polyolefin sheath, face issues with interfacial bond strength due to incompatibility between the two polymers, leading to shedding and separation during processing.
Innovation Solution
Incorporating a polypropylene blend with maleic anhydride-grafted polypropylene and an inorganic Brønsted-Lowry acid into the sheath region of the bicomponent fiber, which improves the adhesion with the PET core through enhanced bonding conditions during coextrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PET core and polyolefin sheath are used in a bicomponent fiber, then the fiber can achieve diverse functional properties, but the interfacial bond strength between the core and sheath deteriorates due to polymer incompatibility
Solution Approach 1:
A polyolefin blend containing maleic anhydride-grafted polypropylene is introduced as an intermediary layer between the PET core and polyolefin sheath. The maleic anhydride groups in the blend react with the PET core to form strong interfacial bonds, while the polyolefin matrix maintains compatibility with the sheath, thus resolving the incompatibility issue between the core and sheath materials
Solution Approach 2:
The sheath region is formulated as a composite material consisting of multiple polyolefin components including maleic anhydride-grafted polypropylene, ethylene-propylene-diene-monomer rubber, and polyethylene. This composite structure provides both the necessary adhesion to the PET core through the maleic anhydride groups and the required compatibility with the polyolefin sheath through the polyethylene matrix
2Strength
If a polyolefin blend with maleic anhydride-grafted polypropylene is used in the sheath region, then the adhesion to the PET core is improved, but the manufacturing complexity of the coextrusion process increases
Solution Approach 1:
The maleic anhydride-grafted polypropylene is pre-blended with the polyolefin sheath material before coextrusion. This preliminary mixing ensures uniform distribution of the adhesive components throughout the sheath region, allowing the bonding action to occur automatically during the extrusion process without requiring additional processing steps or specialized equipment
3Reliability
If the interfacial bond strength is improved through enhanced bonding conditions, then shedding and separation are reduced, but the energy consumption during coextrusion increases
Solution Approach 1:
The bonding action is achieved through chemical parameter changes rather than increased thermal energy input. The maleic anhydride groups undergo chemical reaction with the PET core at relatively low temperatures, forming strong interfacial bonds without requiring excessive heating. This chemical mechanism replaces the need for high-energy thermal bonding processes
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 proposed solution significantly strengthens the interfacial bond between the PET core and the polyolefin sheath, reducing shedding and separation, and enabling higher filament speeds with lower denier values in the bicomponent fibers.
Implementation Method 1
the strength of the interfacial bond between the layers for the bicomponent fiber can be improved by the presence of a maleic anhydride-grafted polypropylene
Implementation Method 2
The polypropylene blend can include 5 to 75 wt.％ of the propylene-based polymer, 2 to 30 wt.％ of the maleic anhydride-grafted polypropylene, and 20 to 10000 parts-per-million of the inorganic Brønsted-Lowry acid
Data Source
AI summary
The present disclosure provides for a bicomponent fiber that includes a first region formed of a condensation polymer and a second region formed from a polypropylene blend. The polypropylene blend includes (i) a propylene-based polymer having a density of 0.895 g/cm3 to 0.920 g/cm3 and a melt index, I2, as determined by ASTM D1238 at 230 oC and 2.16 kg of 0.5 to 150 g/10 minutes; (ii) a maleic anhydride-grafted polypropylene; and (iii) an inorganic Brønsted-Lowry acid having an acid strength pKa value at 25 oC of 1 to 6.5, wherein the polypropylene blend has a 0.03 to 0.3 weight percent of grafted maleic anhydride based on the total weight of the polypropylene blend. The first region is a core region of the bicomponent fiber and the second region is a sheath region of the bicomponent fiber, where the sheath region surrounds the core region.