Prepreg Composition for Composite Impact Resistance
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Solution Overview
Problem
Fiber-reinforced composite materials used in aircraft applications face challenges with impact resistance due to low fracture toughness of thermosetting resins, and automatic lay-up processes often result in fiber or resin adhesion and deposition issues, leading to decreased material properties and increased production time.
Innovation Solution
A prepreg composition comprising carbon fibers, an epoxy resin with multiple glycidyl groups, an aromatic amine compound, a thermoplastic resin with a polyarylether skeleton, and particles of thermoplastic and thermosetting resins, optimized to reduce tackiness and adhesion, while enhancing impact resistance and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermoplastic resin with excellent toughness (polyamide or polycarbonate) is disposed near the surface of the prepreg to improve impact resistance, then impact resistance is improved, but high temperature and high humidity and chemical resistance are weakened
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where different thermoplastic resins are positioned at different locations within the prepreg. Specifically, a first thermoplastic resin layer (polyamide or polycarbonate) is disposed near the surface to provide impact resistance, while a second thermoplastic resin layer (polyimide or polyamide-imide) is disposed in the interior to provide high temperature and chemical resistance. This spatial differentiation of material properties resolves the contradiction between impact resistance and environmental resistance.
Solution Approach 2:
The patent uses composite materials by combining multiple thermoplastic resins with different properties within a single prepreg structure. The combination of polyamide/polycarbonate (for toughness) with polyimide/polyamide-imide (for thermal and chemical stability) creates a composite system that achieves both impact resistance and environmental resistance simultaneously, rather than relying on a single resin type.
2Object-generated harmful factors
If the viscosity of the matrix resin is increased to decrease adherence (tackiness) of the prepreg, then adhesion to automatic lay up device is reduced, but adhesion between the prepregs is impaired and the lay up work is hindered
Solution Approach 1:
The patent applies parameter changes by carefully controlling the viscosity of the matrix resin within a specific range (500-5000 mPa·s at 25°C) and adjusting the glass transition temperature of the thermoplastic resin (80-200°C). By optimizing these parameters, the prepreg achieves reduced tackiness to the automatic lay up device while maintaining sufficient adhesion between prepreg layers during lamination.
Solution Approach 2:
The patent utilizes the dynamic properties of the thermoplastic resin by selecting materials with specific glass transition temperatures (80-200°C). The thermoplastic resin exhibits different adhesive properties at different temperatures: at room temperature it provides low tackiness to the lay up device, while during heating in the lamination process it becomes more adhesive to bond prepreg layers together, thus resolving the contradiction through temperature-dependent behavior.
Data Source
AI summary
A prepreg contains components [A] to [E], wherein 85% by mass or more of the component [E] is present in a range within 9% of the average thickness of the prepreg from each surface of the prepreg, and a range within 7% of the average thickness of the prepreg from each surface of the prepreg is composed of a first resin composition containing components [B] to [E].[A] a carbon fiber,[B] an epoxy resin having two or more glycidyl groups in one molecule,[C] an aromatic amine compound,[D] a thermoplastic resin having a polyarylether skeleton, and[E] particles having a number average primary particle size of 5 to 50 μm, having a content ratio (% by mass) of thermoplastic resin and thermosetting resin of 95:5 to 70:30.