Multi-layer Anti-fog Film Air Gap Plasticizer Migration

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Solution Overview

Problem

Conventional multi-layer anti-fog films experience degradation, brittleness, and haziness due to plasticizer migration, particularly when diethyl phthalate or other plasticizers come into contact with pins or connectors, leading to poor durability and clarity issues in applications like helmets and visors.

Innovation Solution

A multi-layer anti-fog composition featuring a cellulose acetate anti-fog layer with a haloalkyl phosphate plasticizer and a protective polycarbonate layer, where an air gap is defined between the layers to minimize plasticizer migration, and a connector with the same composition as the protective layer is used to secure the orientation, preventing direct contact and enhancing compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional plasticizers like diethyl phthalate are used in the anti-fog layer, then the anti-fog properties are achieved, but plasticizer migration occurs causing degradation, brittleness, and haziness in the protective layer and connectors

Engineering Contradiction:
Improveanti-fog performanceVSAvoidplasticizer migration causing degradation and haziness
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an air gap as an intermediary barrier between the anti-fog layer containing plasticizer and the protective layer containing connectors. This physical separation prevents direct contact and migration of plasticizer from the anti-fog layer to the protective layer and connectors, thereby eliminating degradation and haziness while maintaining anti-fog performance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent divides the multi-layer film into distinct separated layers with an air gap between them. Instead of having direct contact between layers, the structure is segmented into: (1) anti-fog layer with plasticizer, (2) air gap, (3) protective layer with connectors. This segmentation prevents harmful interactions while preserving individual layer functions

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If pins or connectors extend through the anti-fog layer to secure orientation, then mechanical stability is achieved, but direct contact causes plasticizer migration and material degradation

Engineering Contradiction:
Improvemechanical stabilityVSAvoidmaterial compatibility and durability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The air gap acts as an intermediary barrier that prevents connectors from directly contacting the plasticizer in the anti-fog layer. Connectors pass through the air gap space without penetrating the anti-fog layer, thereby maintaining mechanical stability while preventing plasticizer migration and material degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the connectors from direct contact with the anti-fog layer by positioning them in the air gap region. The connectors are taken out of the harmful environment where they would otherwise contact and degrade from plasticizer exposure, while still serving their mechanical function

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3625290B1Multi-layer Anti-fog compositions and processes for making same
Publication Date: 2021.12.22 CELANESE INTERNATIONAL CORP
  • EP3625290B1 patent drawingFigure 1~3
  • EP3625290B1 patent drawing

AI summary

Multi-layer anti-fog compositions comprising an anti-fog layer and a protective layer. The anti-fog layer comprises cellulose acetate and a plasticizer and has opposing major planar surfaces. The protective layer has opposing major planar surfaces that are oriented substantially coplanar, at least in part, to the anti-fog layer that forms a multi-layered structure. The multi-layer anti-fog compositions further comprise one or more connectors, and at least one of the connectors extends through the multi-layered structure.