Inductive Adhesive Tape with Conductive Fillers

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Solution Overview

Problem

Existing heat-activated adhesive systems for plastic-plastic bonding face challenges in achieving high-strength bonds efficiently, particularly in miniaturized electronic devices, due to limitations in heat transfer and potential damage from high-frequency electromagnetic fields, and the use of nanoparticulate fillers is economically and ecologically unfavorable.

Innovation Solution

A heat-activatable adhesive tape with an inductively heatable material and a thermally conductive filler that has high thermal conductivity in the z-direction, maintaining dielectric strength and allowing for efficient heat distribution, thereby enabling high-strength plastic-plastic bonds through induction heating without the need for external heat sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If direct heating or contact heating is used to heat the bonding substrate, then the heating time can be shortened and homogeneous heating can be achieved, but the bonding substrate must be insensitive to high temperatures which can considerably higher than required to activate the adhesive

Engineering Contradiction:
Improveheating timeVSAvoidtemperature sensitivity of bonding substrate
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary heating mechanism by incorporating inductively heatable particles (such as ferrite or iron oxide particles) directly into the adhesive layer. This allows heat to be generated within the adhesive itself through electromagnetic induction, rather than heating the substrate first and hoping heat transfers efficiently. The intermediary particles convert electromagnetic energy directly into heat at the bonding interface, solving the contradiction by eliminating the need for high substrate temperatures while achieving rapid and homogeneous heating of the adhesive.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/thermal contact heating system with an electromagnetic induction heating system. Instead of using external heat sources that require thermal conduction through the substrate, the invention uses electromagnetic fields to directly induce currents in the particles embedded in the adhesive, generating heat inductively. This substitution allows for rapid heating without requiring the substrate to withstand high temperatures, as the heat is generated directly in the adhesive layer.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If inductively heatable particles are used for internal heating of the surface element, then heating can be achieved without external heat sources, but the heating efficiency decreases at lower frequencies and requires a minimum size of conductive domains

Engineering Contradiction:
Improveself-heating capabilityVSAvoidheating efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent optimizes the parameters of the inductively heatable particles, specifically their size, shape, and magnetic properties, to achieve efficient heating across a range of frequencies. By carefully selecting particle dimensions and magnetic characteristics (such as coercivity and saturation magnetization), the adhesive can be effectively heated at both high and lower frequencies. The particle parameters are tuned to resonate with the applied electromagnetic field frequency, maximizing heating efficiency without requiring excessively high frequencies.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials combining the adhesive matrix with dispersed inductively heatable particles (such as ferrite, iron oxide, or other magnetic particles). This composite structure allows the adhesive to possess both its adhesive functions and the ability to convert electromagnetic energy into heat. The composite nature enables the system to achieve self-heating capability while maintaining adequate heating efficiency across different frequencies by optimizing the particle distribution, concentration, and magnetic properties within the adhesive matrix.

Inventive Principle:
Principle #40Composite materials

3Strength

If nanoparticulate fillers are used to enable inductive heating, then high-strength bonds can be achieved, but the manufacturing costs increase and ecological concerns arise

Engineering Contradiction:
Improvebonding strengthVSAvoidmanufacturing cost and ecological impact
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent employs relatively inexpensive, abundant magnetic particles (such as ferrite or iron oxide particles) that can be easily incorporated into the adhesive during manufacturing. These particles are much cheaper than nanoparticulate fillers and do not pose the same ecological concerns regarding nanoparticle disposal and environmental impact. The particles are used in concentrations that provide sufficient inductive heating capability without requiring expensive materials, thereby reducing manufacturing costs and ecological footprint while still achieving high-strength bonds.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the essential function of inductive heating from the problematic nanoparticulate fillers and implements it using simpler, more economical magnetic particles. By removing the nanoparticle requirement and using conventional-sized magnetic particles instead, the invention eliminates the need for expensive nanoparticle synthesis and handling processes, reduces manufacturing complexity, and avoids the ecological issues associated with nanoparticle disposal, while maintaining the core functionality of inductive heating for achieving high-strength bonds.

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

The solution achieves higher bonding strengths and faster heating rates while minimizing the risk of local overheating and maintaining dielectric strength, thus overcoming the limitations of prior art in heat transfer and electromagnetic field exposure.

Implementation Method 1

heating by means of electrical resistance heating, by magnetic induction or as a result of an interaction with microwave radiation

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the material of the filler having a thermal conductivity of at least 0.5 W/(m*K)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2516572B1Heat-activated, glueable surface elements
Publication Date: 2018.06.13 TESA SE
  • EP2516572B1 patent drawingFigure 1

AI summary

The invention relates to a surface element comprising at least one heat-activatable adhesive compound, at least one inductively heatable material and at least one thermally conductive filler, characterized in that the material of the filler has a thermal conductivity of at least 0,5 W/(m*K).