Bicomponent Fiber Sheath Compatibilization
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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 polymers, leading to shedding and separation during processing.
Innovation Solution
Incorporating a polyethylene blend with maleic anhydride-grafted polyethylene and an inorganic Brønsted-Lowry acid into the sheath region of the bicomponent fiber, which improves the adhesion between the PET core and the polyolefin sheath by enhancing the interfacial bond strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a core-sheath bicomponent fiber structure is used with PET core and polyolefin sheath, then the fiber can achieve multiple functional properties from different polymers, but the interfacial bond strength between core and sheath deteriorates due to polymer incompatibility
Solution Approach 1:
The patent introduces a compatibilizer component that acts as an intermediary between the PET core and polyolefin sheath. This compatibilizer contains functional groups that can interact with both polymers, creating a bridging effect that improves interfacial adhesion. The compatibilizer is incorporated into the sheath polymer matrix, allowing it to migrate to the interface and reduce interfacial tension between the incompatible polymers.
Solution Approach 2:
The patent creates a composite sheath material by blending polyolefin with compatibilizer components. This composite approach allows the sheath to maintain its base polyolefin properties while incorporating additional functional components that improve interfacial bonding. The composite structure enables simultaneous achievement of structural integrity and enhanced adhesion.
2Ease of manufacture
If conventional polyolefin is used for the sheath region, then the fiber structure is simple and easy to manufacture, but shedding and separation occur during carding and post-spinning processes
Solution Approach 1:
The patent modifies the chemical and physical parameters of the sheath polymer by incorporating compatibilizers with specific functional groups and molecular weights. These parameter changes enhance the sheath's adhesion properties without fundamentally altering the polyolefin base structure, maintaining ease of manufacture while improving reliability during processing.
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 improves the adhesion between the core and sheath regions, reducing shedding and separation during processing, and enhancing the overall strength and stability of the bicomponent fiber.
Implementation Method 1
a maleic anhydride-grafted polyethylene
Implementation Method 2
an inorganic Brønsted-Lowry acid having an acid strength pKa value at 25° C. of 1 to 6.5
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 polyethylene blend. The polyethylene blend includes (i) an ethylene-based polymer having a density of 0.920 g/cm3 to 0.970 g/cm3 and a melt index, I2, as determined by ASTM D1238 at 190° C. and 2.16 kg of 0.5 to 150 g/10 minutes; (ii) a maleic anhydride-grafted polyethylene; and (iii) an inorganic Brønsted-Lowry acid having an acid strength pKa value at 25° C. of 1 to 6.5, wherein the polyethylene blend has a 0.03 to 0.5 weight percent of grafted maleic anhydride based on the total weight of the polyethylene 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.