Uncrosslinked Adhesive Tape for Epoxy Composite Temporary Fixation

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Solution Overview

Problem

Current methods for temporarily fixing fiber structures during epoxy composite production, such as edge bonding or using spray adhesives, are complex, prone to errors, and introduce foreign materials that degrade the performance of the final composite, especially in demanding industries like aerospace and wind turbine rotor blade production.

Innovation Solution

Employing an uncrosslinked pressure-sensitive adhesive tape that dissolves in the final epoxy resin, allowing for easy and precise temporary fixation without significant impact on the interlaminar shear strength of the final composite, using a hardener-free or latent hardener epoxy adhesive system to ensure minimal disruption to the composite's properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spray adhesives are used for temporary fixing, then the fiber structures can be held in position, but foreign materials are introduced that reduce the composite's performance

Engineering Contradiction:
Improvetemporary fixing reliabilityVSAvoidperformance degradation from foreign materials
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive is extracted from external spray applications and integrated directly into the fiber structure as prepregs, eliminating the need for separate adhesive application and reducing foreign material introduction

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive and fiber structures are merged into a single integrated component (prepreg), where the adhesive is impregnated into the fiber mat before placement, ensuring uniform distribution and eliminating separate adhesive layers

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If edge gluing is used for temporary fixing, then the fiber structures can be secured, but the process becomes complex and error-prone

Engineering Contradiction:
Improvetemporary fixing reliabilityVSAvoidfixing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The adhesive application is segmented into pre-impregnated zones within the fiber mat itself, allowing multiple bonding areas to be prepared simultaneously in a single manufacturing step rather than requiring sequential edge-by-edge application

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive is applied in advance during prepreg manufacturing, creating pre-cut, pre-adhesived sections that can be directly placed and bonded without on-site adhesive application, eliminating complex positioning and application steps

Inventive Principle:
Principle #10Preliminary action

3Reliability

If spray adhesives are used for temporary fixing, then the fiber structures can be positioned, but the application rate depends on the user and uniformity cannot be guaranteed

Engineering Contradiction:
Improvetemporary fixing reliabilityVSAvoidadhesive layer uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The prepreg structure is self-adhesive through the impregnated adhesive, eliminating the need for user-controlled spray application and ensuring consistent adhesive distribution through controlled manufacturing processes

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The adhesive application transitions from user-controlled variable spray rates to factory-controlled precise impregnation parameters, ensuring uniform adhesive distribution through controlled resin flow and saturation during prepreg manufacturing

Inventive Principle:
Principle #35Parameter changes

4Reliability

If spray adhesives containing solvents are used, then the fiber structures can be fixed, but harmful substances must evaporate before bonding

Engineering Contradiction:
Improvetemporary fixing reliabilityVSAvoidevaporation time before bonding
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The adhesive system transitions from solvent-based to solvent-free or water-based formulations, eliminating the need for evaporation time and allowing immediate bonding after placement

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Harmful solvent components are extracted from the adhesive formulation, replacing them with environmentally benign alternatives that do not require evaporation, thereby eliminating the time delay before bonding

Inventive Principle:
Principle #2Taking out (Extraction)

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 method provides a simple, error-resistant, and solvent-free temporary fixation that maintains the high performance of the final composite, with interlaminar shear strength deviations of less than 8%, ensuring design flexibility and avoiding performance losses.

Implementation Method 1

the temporary fixing adhesive of an adhesive tape dissolves in the final fixing adhesive

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

an uncrosslinked pressure-sensitive adhesive tape that dissolves in the final epoxy resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3292177B1Method for manufacturing of a composite made from a fibrous material and an adhesive strip having a temporary fixing adhesive
Publication Date: 2021.06.23 TESA SE
  • EP3292177B1 patent drawingFigure 1

AI summary

The invention relates to an adhesive strip, containing a temporary fixing adhesive for a first temporary fixing of two substrates to one another as a preliminary stage to a second final fixing of the two substrates, wherein the second final fixing takes place by means of a final fixing adhesive and said final fixing adhesive assimilates the temporary fixing adhesive during the second final fixing, wherein the temporary fixing adhesive is a non-crosslinked bonding adhesive and dissolves in the final fixing adhesive during the second final fixing, making it possible to fix fibrous structures temporarily in the epoxy composite production, without negatively influencing the performance of the cured components.