Fiber-Reinforced Hollow Molding with Soft Resin-Integrated Sheets
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Solution Overview
Problem
Conventional fiber reinforced resin materials, such as prepregs, are difficult to handle and mold due to their hardness and poor softness, leading to inefficiencies in processing and potential defects like voids or wrinkles, especially in hollow molding applications.
Innovation Solution
A resin-integrated fiber sheet comprising unidirectional continuous fibers and thermoplastic resin is used, which is wound and consolidated to form a hollow molded body, allowing for direct molding and efficient impregnation of the resin into the fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prepregs obtained by fully impregnating resin are used, then impact resistance is improved and molding time is reduced, but hardness increases and softness deteriorates making them hard to roll up
Solution Approach 1:
The patent uses semipregs with partial resin impregnation instead of full impregnation. The resin content is controlled to provide adequate adhesion and impact resistance while maintaining sufficient softness and rollability for handling and molding operations.
2Ease of operation
If semipregs with no or semi-impregnated resin are used, then softness is improved and shape-ability is enhanced, but molding efficiency may be reduced due to handling requirements
Solution Approach 1:
The patent optimizes the resin impregnation parameters of semipregs to achieve the right balance. By controlling resin content, viscosity, and impregnation degree, the material maintains excellent shape-ability for complex hollow molding while enabling direct molding processes that preserve high productivity.
3Strength
If continuous fibers are used for fiber reinforced resin, then mechanical properties are improved, but fiber misalignment and defects such as voids or wrinkles may occur
Solution Approach 1:
The patent uses pre-oriented continuous fibers in semipreg form where the fibers are already aligned in the desired direction before molding. This preliminary orientation prevents misalignment during the molding process and reduces defects like voids and wrinkles while maintaining high mechanical properties.
4Ease of operation
If staple fibers are processed into nonwoven fabric for fiber reinforced resin, then handling is improved, but processing efficiency is greatly reduced
Solution Approach 1:
The patent combines continuous fibers with thermoplastic resin to create semipreg composite materials. This composite structure provides both the handling advantages of resin-bonded fibers and the processing efficiency of continuous fiber reinforcement, avoiding the need to process staple fibers into nonwoven fabrics.
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 method enables the production of thin, high-quality hollow molded bodies with improved shape-ability and reduced molding cycle time, while minimizing voids and defects, and maintaining mechanical properties.
Implementation Method 1
The thermoplastic resin is impregnated in the unidirectional continuous fibers
Implementation Method 2
the thermoplastic resin is present at least on a surface of the unidirectional continuous fibers
Data Source
AI summary
A fiber reinforced resin hollow molded body 30 in which a resin-integrated fiber sheet is used. The resin-integrated fiber sheet includes unidirectional continuous fibers that are spread fibers of a continuous fiber group and arrayed unidirectionally in parallel, and thermoplastic resin that is present at least on a surface of the unidirectional continuous fibers. In the hollow molded body, in a state where the resin-integrated fiber sheet or a plurality of the resin-integrated fiber sheets 30 are stacked, the resin-integrated fiber sheet or the plurality of resin-integrated fiber sheets are wound to produce a wound body having an overlapping portion. The thermoplastic resin is impregnated in the unidirectional continuous fibers. The resin-integrated fiber sheet or the plurality of resin-integrated fiber sheets are consolidated.