Multi-layered Fiber Core-shell Structure for Low-temperature Consolidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high temperature and pressure requirements for consolidating thermoplastic fibers, such as polypropylene, hinder the co-processing with other materials and increase manufacturing costs due to the need for large metal molds.
Innovation Solution
A multi-layered fiber design featuring a core with a skin layer composed of a first polymer with high α-olefin units and a second polymer with specific molecular weight and viscosity characteristics, allowing for lower temperature and pressure processing while maintaining performance attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature and pressure are used to consolidate thermoplastic fibers, then consolidation performance is achieved, but processing temperature and pressure requirements increase
Solution Approach 1:
The patent modifies the chemical composition parameters of the polymer materials to achieve consolidation at lower temperatures. Specifically, it uses a core-shell fiber structure where the shell contains polymers with lower melting points than the core, enabling the shell to soften and bond at reduced temperatures while the core maintains structural integrity. This parameter change in material composition directly resolves the contradiction by decoupling the temperature requirements for consolidation from those needed for maintaining fiber performance.
Solution Approach 2:
The patent employs composite material design by creating multi-layered fibers with different polymer compositions in the core and shell. The core uses high-performance polymers (e.g., polypropylene, Kevlar®, Twaron®) while the shell uses polymers with lower melting points. This composite structure allows the shell to provide bonding functionality at lower temperatures without compromising the core's high-temperature performance, thus resolving the contradiction between consolidation temperature and final product performance.
2Reliability
If high pressure is applied during consolidation, then fiber bonding is achieved, but manufacturing cost increases due to large metal molds
Solution Approach 1:
The patent changes the thermal parameters of the fiber materials to enable consolidation at lower pressures. By incorporating shell materials with lower melting points, the fibers can be bonded through thermal softening at reduced pressure levels, eliminating the need for high-pressure equipment and large metal molds. This parameter change directly addresses the contradiction by reducing both pressure requirements and associated manufacturing costs.
3Reliability
If high temperature processing is used, then consolidation is achieved, but energy consumption increases
Solution Approach 1:
The patent fundamentally changes the temperature parameter required for consolidation by using shell materials with lower melting points. This allows the consolidation process to occur at significantly reduced temperatures, directly reducing the energy input required for heating. The lower melting point shell materials enable thermal bonding to proceed at temperatures that consume less energy while still achieving effective fiber consolidation.
4Strength
If polypropylene fibers are processed, then structural performance is achieved, but co-processing with other materials is hindered
Solution Approach 1:
The patent uses composite material design with a core-shell structure where the core provides structural performance (using materials like polypropylene, Kevlar®, or Twaron®) and the shell provides processing compatibility (using polymers with lower melting points). This composite structure enables co-processing of polypropylene fibers with other materials that have different thermal properties, as the shell acts as a thermal buffer and bonding interface. The core maintains the required structural performance while the shell enables versatile co-processing, resolving the contradiction between strength and adaptability.
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
Enables the consolidation of fibers at reduced temperatures and pressures, reducing manufacturing costs and energy consumption while achieving comparable or better performance characteristics.
Implementation Method 1
The first polymer contains a polymer having at least 70% α-olefin units and is characterized by a melting temperature lower than the melting temperature of the exterior surface portion of the core. The second polymer contains a co-polymer having at least 50% α-olefin units and is characterized by a melting temperature lower than the melting temperature of the exterior surface portion of the core.
Data Source
AI summary
A multi-layered fiber containing a core and a skin layer. The core has an exterior surface portion containing polypropylene. The skin layer is disposed on at least a portion of the core and contains a first polymer and a second polymer. The first polymer contains a polymer having at least 70% α-olefin units and is characterized by a melting temperature lower than the melting temperature of the exterior surface portion of the core. The second polymer contains a co-polymer having at least 50% α-olefin units and is characterized by a number-average molecular weight of about 7,000 g/mol to 50,000 g/mol, a viscosity of between about 2,500 and 150,000 cP measured at 170° C., and a melting temperature lower than the melting temperature of the exterior surface portion of the core. The viscosity of the second polymer is not greater than about 10 percent of the viscosity of the first polymer measured at 170° C. Methods of forming the multi-layered fiber are also disclosed.