Thermoplastic Prepreg Structure for Complex-Shape Fiber Reinforcement

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Solution Overview

Problem

Existing fiber-reinforced plastics face limitations in achieving high mechanical properties, lightweight properties, and shape followability, particularly in molding complex shapes, due to anisotropy and interference between discontinuous fibers.

Innovation Solution

A thermoplastic prepreg is developed by impregnating a discontinuous reinforcing fiber web with a thermoplastic resin, featuring incisions and a fiber length variation region with a coefficient of variation of 40% or more, and orienting fibers in three or more directions to enhance shape followability and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If unidirectional continuous reinforcing fibers are used in a prepreg, then mechanical properties are improved, but shape followability to complicated shapes is limited due to anisotropy

Engineering Contradiction:

Improvemechanical propertiesVSAvoidshape followability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The continuous reinforcing fibers are divided into discontinuous fibers through incisions, allowing the material to be segmented into multiple directions while maintaining reinforcement effectiveness. This segmentation enables the prepreg to conform to complicated shapes without the anisotropy limitations of unidirectional continuous fibers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite structure combining discontinuous reinforcing fibers with a matrix resin, where the discontinuous fibers provide multi-directional reinforcement while the matrix resin binds them together. This composite approach achieves both mechanical properties and shape followability that cannot be obtained with single continuous fiber orientations.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If discontinuous fibers are dispersed in multiple directions to improve shape followability, then shape followability is enhanced, but fiber interference occurs reducing mechanical properties

Engineering Contradiction:

Improveshape followabilityVSAvoidmechanical properties

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

By dividing continuous fibers into discontinuous segments through incisions, the patent creates a structure where fibers are distributed in multiple directions without the interference problems of completely random discontinuous fibers. The segmentation allows controlled multi-directional arrangement that maintains mechanical integrity while improving shape followability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The incisions create local variations in fiber distribution and orientation, allowing different regions of the prepreg to have optimized fiber arrangements. This local quality control enables the material to adapt to complicated shapes while maintaining adequate mechanical properties in critical areas.

Inventive Principle:

Principle #3Local quality

3Weight of moving object

If a core material with low specific gravity is used to achieve lightweight properties, then lightweight properties are improved, but mechanical properties deteriorate

Engineering Contradiction:

Improvelightweight propertiesVSAvoidmechanical properties

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent uses a composite structure combining discontinuous reinforcing fibers with a matrix resin to achieve lightweight properties without sacrificing mechanical strength. The discontinuous fiber arrangement provides reinforcement while the overall composite structure maintains low density, eliminating the need for heavy skin materials that would compromise lightweight goals.

Inventive Principle:

Principle #40Composite materials

4Strength

If skin material is added to ensure mechanical properties of molded articles, then mechanical properties are improved, but mass increases and thickness must increase

Engineering Contradiction:

Improvemechanical propertiesVSAvoidmass

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The discontinuous fiber-reinforced composite material provides sufficient mechanical properties throughout the entire molded article structure, eliminating the need for additional heavy skin materials. The multi-directional fiber distribution ensures adequate strength and stiffness in all regions without requiring increased thickness or mass.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12576558B2Thermoplastic prepreg, fiber-reinforced plastic, and manufacturing method therefor

Publication Date: 2026.03.17 TORAY INDUSTRIES INC

AI summary

A fiber-reinforced plastic capable of coping with a more complicated shape while maintaining lightweight properties and mechanical properties is provided, where a thermoplastic prepreg is obtained by impregnating a discontinuous reinforcing fiber web impregnated with a thermoplastic resin, the thermoplastic prepreg satisfying at least one of the following features (A) or (B):feature (A): a plurality of incisions cutting at least a part of discontinuous reinforcing fibers constituting the discontinuous reinforcing fiber web; andfeature (B): a fiber length variation region in which a coefficient of variation in fiber length of the discontinuous reinforcing fibers constituting the discontinuous reinforcing fiber web is 40% or more.