Multilayer Composite with Miscible Resins for Aircraft Interiors
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Solution Overview
Problem
Existing multilayer composites for vehicle components, such as aircraft interiors, face challenges in achieving sufficient strength, modulus, flame retardancy, low smoking properties, and ease of shape and density adjustment due to complex production processes and inadequate integration of core and skin layers.
Innovation Solution
A multilayer composite structure comprising a core layer with randomly dispersed discontinuous reinforcing fibers and a thermoplastic resin, combined with a skin layer of continuous reinforcing fibers and a miscible thermoplastic resin, which are heat-compressed and expanded to enhance adhesion and physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a sandwich structure with core layer and skin layer is used for weight reduction, then weight decreases and fuel efficiency improves, but production process becomes complicated and productivity decreases
Solution Approach 1:
The patent merges the core layer and skin layer into a single integrated nonwoven fabric structure, eliminating the need for separate bonding processes. The continuous reinforcing fibers provide skin layer functionality while the thermoplastic resin binding provides core layer characteristics, achieving weight reduction without complicating the production process.
Solution Approach 2:
The patent uses composite materials by combining continuous reinforcing fibers (for strength and stiffness) with thermoplastic resin (for binding and flame retardancy). This composite structure provides both the mechanical properties of a sandwich structure and the production simplicity of a single-layer nonwoven fabric.
2Object-affected harmful factors
If polyimide fibers are used for flame retardancy and low smoking property, then flame retardancy improves, but strength and modulus become insufficient
Solution Approach 1:
The patent combines polyimide fibers (providing flame retardancy and low smoking property) with continuous reinforcing fibers (providing strength and modulus). The continuous fibers create a load-bearing network that compensates for the relatively low mechanical strength of polyimide fibers alone, while the thermoplastic resin binding holds the structure together.
Solution Approach 2:
The patent assigns different functions to different components: polyimide fibers are distributed throughout to provide flame retardancy, while continuous reinforcing fibers are arranged to provide structural strength. The thermoplastic resin binding provides both mechanical binding and additional flame retardancy, creating local functional zones within the material.
3Object-affected harmful factors
If scrim or film is used as skin layer for flame retardancy, then flame retardancy improves, but integrity of composite material becomes poor
Solution Approach 1:
The patent uses a composite nonwoven fabric structure where continuous reinforcing fibers are bound by thermoplastic resin, creating an integrated structure that combines the flame retardancy of materials like polyimide with the integrity provided by the continuous fiber network and resin binding system.
Solution Approach 2:
The patent creates a homogeneous distribution of flame-retardant fibers throughout the nonwoven fabric structure, rather than using separate scrim or film layers. This homogeneous integration ensures that flame retardancy and structural integrity are combined in a single unified material system.
4Weight of moving object
If discontinuous reinforcing fibers are used for lightweight structure, then weight decreases, but form-moldability and shape adjustment become difficult
Solution Approach 1:
The patent uses thermoplastic resin binding that can be softened by heating, allowing the nonwoven fabric to be molded into different shapes. The thermoplastic properties enable parameter changes in the material's physical state, facilitating form-moldability while maintaining the lightweight discontinuous fiber structure.
Solution Approach 2:
The patent incorporates thermoplastic resin binding during the nonwoven fabric formation process, creating a pre-bound structure that maintains its shape during handling but can be re-shaped through thermal processing. This preliminary binding provides structural stability while allowing subsequent shape adjustment.
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 solution provides a composite with excellent flame retardancy, low smoking properties, high physical characteristics, and ease of shape and density adjustment through thermal expansion molding, suitable for applications in aircraft and railway car interiors.
Implementation Method 1
heating of the base material makes the polyimide fibers, which are a thermoplastic resin, softened so that bending stress of the reinforcing fibers is released to cause the reinforcing fibers to expand
Implementation Method 2
the reinforcing fibers to expand, thereby making it possible to obtain a base material with lightweight and good form-moldability
Implementation Method 3
the first and the second thermoplastic resins are miscible with each other
Data Source
AI summary
Provided is a multilayer composite that has flame retardancy and low smoking property as well as has high physical characteristics. The multilayer composite has a multilayer structure and includes at least one core layer and at least one skin layer, wherein the multilayer composite satisfies all the following conditions (A) to (D): (A) the core layer is a composite including discontinuous reinforcing fibers and a first thermoplastic resin, in which the discontinuous reinforcing fibers are randomly dispersed and bonded with the first thermoplastic resin at least at intersections of the discontinuous reinforcing fibers; (B) the skin layer is a composite including continuous reinforcing fibers and a second thermoplastic resin, in which the continuous reinforcing fibers are impregnated with the second thermoplastic resin; (C) each of the first and the second thermoplastic resins has a limiting oxygen index of 30 or higher; and (D) the first and the second thermoplastic resins are miscible with each other.