Multi-Layer Packaging Coating for Recyclable Barrier Durability

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Solution Overview

Problem

Existing multi-layer packaging materials with cellulose-based layers and plastic or metal films face issues with recyclability, mechanical weakness, and degradation of barrier properties under mechanical stress, particularly due to hygroscopic polyvinylalcohols and low adhesion of polymer layers, leading to delamination and reduced gas and moisture barriers.

Innovation Solution

A multi-layer packaging material comprising a cellulose-based layer, a tie coating layer with a polymeric binder, intermediate polyvinyl alcohol layers, and a vacuum deposited metallization layer, along with inner polymeric coating layers, to enhance adhesion, mechanical resilience, and maintain barrier properties under stress, while being recyclable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If butylvinylalcohol (BVOH) is used as pre-metallization and post-metallization coating layers, then adhesion and barrier properties are improved, but hygroscopic nature causes humidity absorption and degradation of barrier properties

Engineering Contradiction:

Improvebarrier propertiesVSAvoidhumidity absorption

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A polyethylene terephthalate (PET) intermediate layer is introduced between the cellulose-based paper layer and the BVOH coating layers. This intermediary layer acts as a barrier to humidity, preventing moisture from the paper substrate from reaching the hygroscopic BVOH layers, thereby maintaining their barrier properties and preventing delamination during twisting and folding operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If plastic layers are deposited in thick layers by extrusion or lamination, then robustness and barrier properties are improved, but recyclability is lost

Engineering Contradiction:

ImproverobustnessVSAvoidrecyclability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention changes the thickness parameter of the plastic layers from thick (conventional extrusion/lamination) to thin (micro-coating technology). The plastic layers are applied at thicknesses of 1-10 micrometers, which provides sufficient barrier properties while maintaining recyclability through pulping processes, as the thin plastic content does not interfere with paper fiber separation.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple polymer layers are combined for barrier properties, then gas and moisture barriers are improved, but adhesion between layers deteriorates under mechanical stress

Engineering Contradiction:

Improvebarrier propertiesVSAvoidadhesion

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

PET intermediate layers are positioned between the cellulose-based paper layer and the BVOH coating layers, and also between multiple BVOH layers. These intermediary PET layers serve as adhesion promoters and stress distributors, preventing direct contact between incompatible polymer layers and reducing delamination during twisting and folding operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If paper layer is used as base material, then recyclability is improved, but mechanical strength and barrier properties deteriorate

Engineering Contradiction:

ImproverecyclabilityVSAvoidbarrier properties

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention creates a composite multi-layer structure combining cellulose-based paper with thin plastic coating layers. The paper provides recyclability and mechanical strength, while the thin plastic layers (1-10 micrometers) deposited by micro-coating technology provide enhanced gas and moisture barrier properties without compromising recyclability through pulping processes.

Inventive Principle:

Principle #40Composite materials

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 provides improved adhesion and barrier properties, maintaining integrity under mechanical stress, and facilitates recycling through conventional paper processes, enhancing the safety and longevity of packaged products.

Implementation Method 1

a vacuum deposited metallization layer

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Implementation Method 2

a tie coating layer comprising a polymeric binder material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20250346417A1Multi-layer packaging material, a package and a method for manufacturing a muti-layer packaging material

Publication Date: 2025.11.13 TORRASPAPEL SAU

AI summary

The disclosure refers to a multi-layer packaging material comprising, from its outermost side to its innermost side, the following layers: a cellulose-based material layer having a grammage from 40 to 120 g/m2; a tie coating layer, the tie coating layer comprising a polymeric binder; an intermediate polymeric coating layer, the intermediate polymeric coating layer comprising a polyvinyl alcohol (PVA) polymer; a vacuum deposited metallization layer; and an inner polymeric coating layer, the inner polymeric coating layer comprising a material selected from a group comprising acrylic copolymers, polyesters, polyurethanes, polyester copolymers, polyurethane copolymers, vinyl acetates copolymers, chloride copolymers and any combination thereof.