Multi-layer Packaging Film Anti-static Inner Layer

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Solution Overview

Problem

Conventional multi-layer films tend to cause particulate materials like leaf tea to stick to the inner layer, making it difficult to dispense all of the material from the package.

Innovation Solution

A multi-layer packaging film with an inner layer of polypropylene and an anti-static agent, an outer layer of polypropylene and an anti-static agent, and an intermediate layer of polyethylene terephthalate or polypropylene, where the intermediate layer is corona-treated on both faces but the inner and outer layers are not, enhancing the film's ability to prevent particulate material from adhering and ensuring effective lamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the inner layer is corona-treated to improve lamination, then lamination quality improves, but particulate material sticks to the inner layer

Engineering Contradiction:
Improvelamination qualityVSAvoidparticulate material adhesion
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies corona treatment selectively only to the intermediate layer (both faces), while leaving the inner and outer layers untreated. This local differentiation allows the intermediate layer to achieve good lamination bonds with adjacent layers, while the untreated inner layer maintains its natural surface properties that prevent particulate adhesion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The intermediate layer serves as a mediator between the inner and outer layers. By corona-treating only this intermediate layer, the patent achieves strong lamination bonds at the interfaces while the inner layer's natural surface acts as a non-stick barrier for particulate materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the inner layer has high surface tension for good lamination, then lamination improves, but particulate material adheres to the inner layer

Engineering Contradiction:
Improvelamination bond strengthVSAvoidparticulate material adhesion
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent creates different surface properties in different layers: the intermediate layer has high surface tension (via corona treatment) for strong lamination, while the inner layer maintains low surface tension (natural state) to repel particulate materials.

Inventive Principle:
Principle #3Local quality

3Productivity

If the film is stored in a roll with inner and outer layers in contact, then storage efficiency improves, but layers may stick together

Engineering Contradiction:
Improvestorage efficiencyVSAvoidlayer separation
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent uses the same material (polypropylene) for both the inner and outer layers, ensuring they have identical surface properties. When stored in contact, both layers exhibit the same low surface energy characteristics that prevent adhesion, allowing efficient roll storage without sticking.

Inventive Principle:
Principle #33Homogeneity

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 film effectively prevents particulate material from sticking to the inner layer, allowing for improved packaging and storage configurations, with excellent lamination properties and no adhesion of tea dust to the package, ensuring reliable packaging performance.

Implementation Method 1

the anti-static agent in the inner layer reduces the surface tension of the inner layer and enables the inner layer to repel even fine particles of particulate material such as tea dust

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

the intermediate layer is corona-treated on both the inner and outer faces

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Data Source

PatentEP3752356B1Multi-layer packaging film
Publication Date: 2021.06.09 UNILEVER PLC

AI summary

Disclosed is a multi-layer packaging film comprising: an inner layer comprising polypropylene and an anti-static agent; an outer layer comprising polypropylene and an anti-static agent; and an intermediate layer comprising polyethylene terephthalate or polypropylene. The intermediate layer has an outer face facing the outer layer and an inner face facing the inner layer and is corona-treated on both the inner and outer faces.