Metallic Net Prepreg for 3D Shape Retention

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Solution Overview

Problem

Existing methods for manufacturing three-dimensional composite motor vehicle components using prepregs result in shape collapse during reheating due to the resin matrix softening, leading to inadequate mechanical strength and complex shape retention.

Innovation Solution

Incorporating a metallic net layer between prepreg layers, which remains solid during reheating, providing structural support and enhancing mechanical strength while maintaining the three-dimensional shape, and being retained in the final overmolded product for supplementary reinforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the three-dimensional preform is reheated to a temperature higher than the melting point of the prepreg resin matrix, then the resin matrix softens and becomes molten for good adhesion in subsequent overmolding, but the three-dimensional preform collapses under gravity

Engineering Contradiction:
Improveadhesion between prepreg resin matrix and overmolded resinVSAvoidthree-dimensional shape of preform
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

A metallic net layer is introduced as an intermediary support structure between the prepreg layers. This metallic net acts as a mediator that provides mechanical support during the reheating process, preventing the preform from collapsing while allowing the resin matrix to soften and achieve good adhesion for overmolding.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure combining organic prepreg layers with an inorganic metallic net. This composite material approach allows the preparation of a semi-product with both flexible resin matrix for adhesion and rigid metallic support for shape maintenance during thermal processing.

Inventive Principle:
Principle #40Composite materials

2Shape

If a metallic layer is added between prepreg layers to maintain three-dimensional shape during reheating, then shape retention is improved, but device complexity increases

Engineering Contradiction:
Improvethree-dimensional shape retentionVSAvoidstructure complexity of semi-product
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The metallic net is designed as a thin, flexible mesh structure rather than a solid rigid layer. This thin-film approach provides sufficient mechanical support for shape retention while minimizing the added complexity and volume of the structure.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The metallic net employs a porous mesh structure with open spaces between the metal wires. This porous design provides structural support while reducing material usage and complexity compared to a solid metallic layer, and allows the resin to penetrate and bond effectively.

Inventive Principle:
Principle #31Porous 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 metallic net layer effectively maintains the three-dimensional shape of the preform during processing, enhances mechanical strength, and reduces product weight and costs by integrating a supplementary reinforcement, while improving adhesion between prepreg layers.

Implementation Method 1

when thermoplastic resin contained in the first prepreg layer and the second prepreg layer is softened, the metal layer still remains in a solid state

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 2

when the three-dimensional preform is reheated to a temperature higher than the melting point of the prepreg resin matrix, the resin matrix changes into a molten state

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

so as to provide the prepreg resin matrix and an overmolded resin with good adhesion in subsequent overmolding

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3072683B1Semi-finished product manufactured from prepreg, three-dimensional preformed body and overmoulded part
Publication Date: 2020.11.04 COMPAGNIE PLASTIC OMNIUM SA
  • EP3072683B1 patent drawingFigure 1~2
  • EP3072683B1 patent drawingFigure 3~5
  • EP3072683B1 patent drawingFigure 6~8J

AI summary

The present invention provides a semi-product made of a prepreg, a three-dimensional preform and an overmolded part. More particularly, the present invention provides a semi-product made of a prepreg, including at least a first prepreg layer and a second prepreg layer, characterized in that a metal layer is laid between the first prepreg layer and the second prepreg layer. Since the metal layer is added between the prepreg layers, the three-dimensional preform made of the semi-product can be supported by the metal layer during a reheating process prior to overmolding, thereby well maintaining its three-dimensional shape without collapsing. In addition, since the added metal layer is retained in a final overmolded product, it can enhance mechanical strength of the product and serve as a supplementary reinforcement.