Textile Connecting Component for Back-Injected Composite Bonding

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Solution Overview

Problem

The connection between structural components and back-injected injection molded components in composite materials is often too weak, leading to undesirable mechanical weak points and limitations in material choice and functional scope.

Innovation Solution

Incorporating a semi-finished textile product as a connecting component that is impregnable with molten plastic, forming a positive and cohesive connection with the structural component and injection molded component, enhancing the connection quality and strength through the use of a textile fabric that can be woven, knitted, or braided with thermoplastic or carbon fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If back-injection is used to improve adhesion between structural component and injection-molded component, then bond strength is improved, but the structural component may be over-injected and fibers may be displaced creating mechanical weak points

Engineering Contradiction:
Improvebond strengthVSAvoidstructural integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A textile connecting component is introduced as an intermediary element between the structural component and the injection-molded component. This connecting component serves as a mediator that receives the back-injected plastic material, allowing it to penetrate and interlock with the textile structure. This controlled penetration into the textile connecting component prevents direct over-injection into the thin structural component, thereby maintaining structural integrity while achieving strong adhesion through the connecting component's mechanical interlocking with both the structural component and the injection-molded component.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If identical base polymers are used in matrix material and plastic to create material-bonded connection, then adhesion is improved, but material choice is limited and functional scope is reduced

Engineering Contradiction:
ImproveadhesionVSAvoidmaterial choice
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The textile connecting component acts as a universal intermediary that can bridge different material systems. The connecting component itself can be made from various textile materials (natural fibers, synthetic fibers, glass fibers, carbon fibers), and the back-injected plastic can be any suitable plastic material. This intermediary approach allows dissimilar materials to be joined effectively without requiring identical base polymers, thereby expanding material choice and functional scope while maintaining strong adhesion through the mechanical interlocking and bonding provided by the connecting component.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If surface roughening or positive-locking connections are created to increase contact area, then adhesion is improved, but additional process steps are required increasing manufacturing complexity

Engineering Contradiction:
ImproveadhesionVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The textile connecting component inherently provides a porous, three-dimensional structure with high surface area and multiple anchoring points. This porous textile structure allows the back-injected plastic material to penetrate deeply and form extensive mechanical interlocking without requiring additional surface roughening steps. The textile's natural porosity and fibrous structure provide the necessary contact area and bonding surface, eliminating the need for separate surface preparation processes and reducing manufacturing complexity.

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

This approach significantly increases the shear strength of the composite component by up to 50% and prevents complete detachment or splintering during overload, providing a resilient reinforcement in the connection zone.

Implementation Method 1

the connecting component is enclosed and/or penetrated by the injection molded component in the back injection section

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the composite sheet is heated above the softening temperature of the thermoplastic material

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

filling the injection mold with thermoplastic material heated above the softening temperature

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4049821B1Composite component and method for manufacturing same
Publication Date: 2023.09.06 UNIVERSITY OF KASSEL
  • EP4049821B1 patent drawingFigure 1a~1b
  • EP4049821B1 patent drawingFigure 2a~2b
  • EP4049821B1 patent drawingFigure 2c

AI summary

The invention relates to a composite component (100) comprising a structural component (1) made of a thermoplastic material or a thermoplastic-based composite material and at least one injection-molded component (2) made of a plastic, wherein the structural component (1) is back-injected with the injection-molded component (2) in a back-injection section (12). According to the invention, the composite component (100) has at least one connecting component (3) made of a textile fabric, wherein the connecting component (3) is enclosed and/or penetrated by the injection-molded component (2) in the back-injection section (12) and wherein the connecting component (3) is connected to the structural component (1) outside the back-injection section (12).