Partially Impregnated Thermoplastic Prepregs for Flexible Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermoplastic prepregs are rigid and not suitable for applications requiring flexibility and conformability due to their high degree of impregnation with thermoplastic resin, making it difficult to mold them into complex shapes.
Innovation Solution
The development of partially impregnated thermoplastic prepregs, where between 40% and 80% of continuous glass fibers remain free of polymer resin, allowing for flexibility and subsequent full impregnation upon heating and pressure, enabling the prepregs to be molded into various shapes while maintaining fiber reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic prepregs are fully impregnated with thermoplastic resin, then fiber reinforcement is achieved, but flexibility and conformability are lost
Solution Approach 1:
The patent applies local quality by creating regions with different impregnation levels: surface regions with full impregnation for strength, and core regions with partial impregnation (40-80% fibers remain free) for flexibility. This gradient structure allows the prepreg to exhibit both reinforcement and conformability simultaneously.
Solution Approach 2:
The patent uses partial action by intentionally leaving 40-80% of fibers free from resin impregnation in the core region, rather than achieving complete saturation. This partial impregnation maintains flexibility while still providing adequate reinforcement, resolving the contradiction between strength and conformability.
2Manufacturing precision
If high temperature and high pressure are used to achieve complete impregnation, then fiber saturation is improved, but prepreg rigidity increases and flexibility decreases
Solution Approach 1:
The patent deliberately applies partial impregnation (40-80% fiber saturation) instead of complete impregnation, using controlled temperature and pressure conditions. This partial action achieves adequate manufacturing precision while preserving the flexibility needed for complex shape molding.
Solution Approach 2:
The patent changes the impregnation parameter from complete saturation to partial saturation (40-80% fiber coverage), which fundamentally alters the prepreg properties. This parameter change enables the material to maintain flexibility while still achieving sufficient fiber reinforcement for structural applications.
3Strength
If thermoplastic resin is applied to impregnate fibers, then composite strength is improved, but processability for complex shapes is reduced
Solution Approach 1:
The patent applies resin selectively: full impregnation at fiber surfaces for strength, and partial impregnation in the core for processability. This local differentiation allows the composite to achieve both high strength and excellent processability for complex geometries.
Solution Approach 2:
By applying partial impregnation (leaving 40-80% of core fibers free), the patent reduces resin content in non-critical regions, thereby improving processability and conformability to complex shapes while maintaining sufficient strength through surface impregnation and coupling agents.
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 partially impregnated prepregs exhibit increased flexibility and conformability, allowing for the formation of intricate shapes and reduced production costs, with improved processability and mechanical properties through full impregnation during subsequent molding processes.
Implementation Method 1
A thermoplastic polymer material is partially impregnated within a reinforcement fabric so that between 40% and 80% of the fibers of the reinforcement fabric remain substantially free of the thermoplastic polymer material
Implementation Method 2
The thermoplastic polymer material is a thermoplastic material that when subjected to a subsequent heating and/or pressure process, melts and fully impregnates the reinforcement fabric by wetting or contacting substantially all of the fibers
Implementation Method 3
the fibers are sized with a coupling agent that promotes bonding between the polymer resin and the continuous glass fibers
Data Source
AI summary
According to one embodiment, a flexible prepreg comprises a woven cloth or fabric partially coated with a polymer resin. The woven cloth or fabric has a first major surface and a second major surface that is positioned on an opposite side of the first surface. Each roving contains a bundle of fibers. A polymer resin coating is positioned atop the first surface of the woven cloth or fabric. The woven cloth or fabric is coated so that at least 30% of the fibers remain substantially free of or uncoated by the polymer resin. The polymer resin includes a thermoplastic material that melts or softens when exposed to a heating process.