Multilayer Film with Hybrid Buffer Layers for High-Temperature Flatness

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Solution Overview

Problem

Current plastic films used in electronic devices suffer from curling, blocking, and sagging when processed at temperatures higher than their glass transition temperature, limiting their usability and requiring improved heat resistance and high-temperature flatness.

Innovation Solution

A multi-layer film is developed with a polymer substrate and buffer layers formed using a UV-cured and thermally cured product of a UV-curable and thermally curable buffer composition, comprising a sol-like mixture of hydrolyzate of organosilane or metal alkoxide and curable epoxy resin, which is processed to inhibit curling and maintain flatness at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If plastic films are processed at temperatures higher than their glass transition temperature, then processing flexibility is improved, but the films exhibit curling, blocking and sagging

Engineering Contradiction:
Improveprocessing flexibilityVSAvoidflatness
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent uses a composite structure consisting of a polymer substrate combined with organic/inorganic hybrid buffer layers. The buffer layers are formed from sol-gel derived materials that provide thermal stability and dimensional control, enabling the plastic film to maintain flatness during high-temperature processing while retaining the flexibility advantages of plastic materials.

Inventive Principle:
Principle #40Composite materials

2Temperature

If glass plates are used instead of plastic films, then heat resistance and flatness are improved, but weight and handling flexibility deteriorate

Engineering Contradiction:
Improveheat resistanceVSAvoidweight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent applies the local quality principle by providing thermal stability only where needed - in the buffer layers adjacent to the polymer substrate - rather than making the entire film structure thermally resistant like glass. The buffer layers locally compensate for thermal expansion differences, providing heat resistance at the interface while the bulk plastic material remains lightweight and flexible.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If buffer layers are added to improve heat resistance, then high-temperature flatness is improved, but device complexity increases

Engineering Contradiction:
Improvehigh-temperature flatnessVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The buffer layers serve multiple functions simultaneously: they provide thermal expansion compensation, improve adhesion between the polymer substrate and other layers, and maintain dimensional stability at high temperatures. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 multi-layer film exhibits improved heat resistance and high-temperature flatness, allowing processing at temperatures below and above its glass transition temperature without curling, blocking, or sagging, and demonstrates enhanced surface hardness and dimensional stability.

Implementation Method 1

UV-cured and thermally cured product of a UV-curable and thermally curable buffer composition

Methodology Applied
Scientific EffectUV curing: Photopolymerisation

Implementation Method 2

UV-cured and thermally cured product of a UV-curable and thermally curable buffer composition

Methodology Applied
Scientific EffectThermal curing: Chemical Bonding

Implementation Method 3

hydrolyzate of organosilane or metal alkoxide

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP2357079B1Multilayer film and a production method for same
Publication Date: 2014.07.16 LG CHEM LTD
  • EP2357079B1 patent drawingFigure 1~2
  • EP2357079B1 patent drawingFigure 3
  • EP2357079B1 patent drawingFigure 4~5

AI summary

Disclosed is a multi-layer film including a polymer substrate and buffer layers formed on the top surface and the bottom surface of the polymer substrate using a UV-cured and thermally cured product of a UV-curable and thermally curable buffer composition. A method for producing the multi-layer film is also disclosed.