Hotmelt Adhesive Encapsulation for Flexible Electronics

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Solution Overview

Problem

Existing encapsulation methods for (opto)electronic arrangements are inadequate in providing a reliable barrier against water vapor and oxygen, leading to reduced performance and longevity due to issues like permeation, mechanical stress, and limited flexibility, especially in flexible organic electronics.

Innovation Solution

A method using a partly crosslinked hotmelt adhesive based on acid-modified or acid anhydride-modified vinylaromatic block copolymers, which is applied to encapsulate electronic arrangements, offering excellent barrier properties, adhesion, and flexibility while avoiding high-temperature processing and mechanical loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass or metal substrates are used for encapsulation, then permeation barrier performance is improved, but mechanical flexibility and transparency deteriorate

Engineering Contradiction:

Improvepermeation barrier performanceVSAvoidmechanical flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs flexible planar substrates consisting of multiple thin film layers (including polymer films and inorganic barrier layers) instead of rigid glass or metal substrates. This multi-layer flexible substrate structure provides both the required permeation barrier performance and mechanical flexibility for flexible (opto)electronic arrangements

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The encapsulation structure uses composite materials combining organic polymer films with inorganic barrier layers to achieve both flexibility and effective permeation protection. The combination of different material types in a multi-layer configuration allows simultaneous achievement of mechanical flexibility and high barrier performance

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional adhesives are used for sealing, then ease of application is improved, but barrier performance against water vapor and oxygen deteriorates

Engineering Contradiction:

Improveease of applicationVSAvoidbarrier performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the adhesive by incorporating specific barrier-forming components and adjusting molecular structure to reduce permeability. The adhesive is formulated with specific polymers and additives that provide both good adhesion properties and effective barrier performance against water vapor and oxygen

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesive used for sealing is a composite material combining polymer matrices with barrier-enhancing additives and functional components. This composite adhesive structure provides both the required adhesion characteristics for easy application and the barrier properties necessary to prevent permeation of water vapor and oxygen

Inventive Principle:

Principle #40Composite materials

3Strength

If high-temperature processing is used for encapsulation, then adhesion strength is improved, but damage to sensitive organic electronic components increases

Engineering Contradiction:

Improveadhesion strengthVSAvoidthermal damage to components

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the processing temperature parameter from conventional high-temperature processing to low-temperature processing (below the degradation temperature of organic electronic components). The adhesive and encapsulation materials are specifically formulated to achieve adequate adhesion strength at these reduced temperatures through modified chemical composition and molecular structure

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents water vapor and oxygen permeation, maintains adhesion at elevated temperatures, and ensures high flexibility, thereby extending the lifetime of (opto)electronic arrangements without forming bubbles between polyester films under storage conditions.

Implementation Method 1

A perceived technical challenge for realization of sufficient lifetime and function of (opto)electronic arrangements in the area of organic and/or inorganic (opto)electronics, but especially in the area of organic (opto)electronics, is the protection of the components they contain against permeants. Permeants may be a large number of low molecular mass organic or inorganic compounds, more particularly water vapour and oxygen.

Methodology Applied

Scientific EffectPermeation barrier: Permeation

Implementation Method 2

an at least partly crosslinked hotmelt adhesive based on acid-modified or acid anhydride-modified vinylaromatic block copolymers

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

The flexible bonding solutions are therefore intended not only to achieve effective adhesion between two substrates

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8771459B2Method of encapsulating an electronic arrangement

Publication Date: 2014.07.08 TESA SE

AI summary

The present invention relates to as method of encapsulating an electronic arrangement with respect to permeants, in which an at least partly crosslinked hotmelt adhesive based on acid-modified or acid-anhydride-modified vinylaromatic block copolymers is provided and in which the pressure-sensitive adhesive is applied to and/or around the regions of the electronic arrangement that are to be encapsulated.