Method for producing a fiber reinforced resin molded body

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Solution Overview

Problem

Conventional methods for producing fiber reinforced composites with carbon fibers suffer from interlaminar fracture due to poor adhesion between short-fiber webs and carbon fiber sheets, leading to delamination and limited interlaminar fracture toughness.

Innovation Solution

A method involving surface-modified carbon fiber sheets with multidirectional fibers derived from unidirectional long-fiber groups, which are integrated with thermoplastic or thermosetting resins, enhancing adhesion and interlaminar fracture toughness through physical anchoring and improved resin-carbon fiber interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If short-fiber webs are arranged between prepregs to enhance interlaminar fracture toughness, then interlaminar fracture toughness is improved, but adhesion between the web and carbon fiber sheets is poor causing delamination

Engineering Contradiction:
Improveinterlaminar fracture toughnessVSAvoidadhesion between web and carbon fiber sheets
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the physical and chemical parameters of the carbon fiber sheet surface by controlling the spreading process and applying tension during manufacturing. This creates surface modifications including cut faces, breakages, and scratches that enhance adhesion. The parameter changes in surface roughness and fiber arrangement enable better bonding between the carbon fiber sheet and matrix resin, resolving the adhesion problem while maintaining high interlaminar fracture toughness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure where multidirectional fibers are integrated with the matrix resin to form a unified carbon fiber sheet. This composite approach combines the high strength of unidirectional fibers with the adhesion benefits of multidirectional surface fibers, achieving both improved interlaminar fracture toughness and reliable adhesion simultaneously.

Inventive Principle:
Principle #40Composite materials

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 approach significantly increases interlaminar fracture toughness by creating a synergistic effect between multidirectional fibers and resin, improving the strength and elastic modulus of the composite, while maintaining high tensile strength in the longitudinal direction.

Implementation Method 1

resin on its surface adhesively fixes bridging fibers oriented across the other, parallel fibers

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3925752B1Method for producing a fiber reinforced resin molded body
Publication Date: 2025.01.01 KURABO INDUSTRIES LTD
  • EP3925752B1 patent drawingFigure 1
  • EP3925752B1 patent drawingFigure 2
  • EP3925752B1 patent drawingFigure 3

AI summary

A fiber reinforced resin molded body, including: resin-integrated carbon fiber sheets 20 that are stacked and unified, each of the resin-integrated carbon fiber sheets 20 including a carbon fiber sheet 21 and at least one resin 23 selected from the group consisting of thermoplastic resin and thermosetting resin. The carbon fiber sheet 21 includes a unidirectional long-fiber group 21a spread and arrayed in one direction, and multidirectional fibers 22a and 22b derived from the unidirectional long-fiber group. The multidirectional fibers 22a and 22b cross carbon fibers constituting the unidirectional long-fiber group. The fiber reinforced resin molded body is a molded body of two or more stacked layers of the resin-integrated carbon fiber sheets 20, or a molded body of the resin-integrated carbon fiber sheet 20 that is stacked with a resin-integrated carbon fiber sheet including a different carbon fiber sheet. Thus, the present invention provides a fiber reinforced resin molded body including a surface-modified carbon fiber sheet and thus having high interlaminar fracture toughness, and a method for producing the carbon fiber sheet for the fiber reinforced resin molded body.