PET Multilayer Container with PEF Barrier Layer for Gas Permeation

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Solution Overview

Problem

Existing PET containers face challenges in gas barrier performance, particularly for carbonated beverages and oxygen-sensitive products, with current enhancements degrading PET properties, impacting stretch ratio, clarity, and mechanical stability.

Innovation Solution

A multilayer PET container design featuring a 2,5-furandicarboxylate polyester barrier layer sandwiched between PET layers, which maintains PET integrity and enhances gas barrier properties without affecting stretch ratio or clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas barrier enhancement additives are incorporated into PET in a monolayer configuration, then gas barrier properties are improved, but PET degradation occurs and intrinsic viscosity deteriorates

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidPET intrinsic viscosity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent divides the container into multiple layers with different functions: outer PET layers provide mechanical strength and clarity, while the inner barrier layer (containing 2,5-furandicarboxylate polyester or other barrier materials) provides gas barrier enhancement. This segmentation allows each layer to optimize its specific function without compromising the overall PET structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses composite multilayer structures combining PET with barrier materials such as 2,5-furandicarboxylate polyester, nylon, EVOH, or PVDC in specific layers. This composite approach achieves superior gas barrier properties while maintaining PET's mechanical properties through proper material selection and layer configuration.

Inventive Principle:
Principle #40Composite materials

2Reliability

If co-monomers are incorporated in preparing the resin or blending with other components, then gas barrier properties are enhanced, but stretching properties are adversely affected and new preform designs are required

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidstretching properties
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of modifying the entire PET structure with co-monomers, the patent segments the barrier enhancement to a specific inner layer. This allows the outer PET layers to maintain their original stretching properties and compatibility with existing preform designs, while the inner barrier layer provides the required gas barrier enhancement.

Inventive Principle:
Principle #1Segmentation

3Reliability

If organic or inorganic coatings are applied to increase resistance to gas permeation, then gas barrier properties are improved, but substantial capital investment for coating equipment is required

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidcoating equipment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates barrier materials directly into the container structure as a co-extruded or co-molded multilayer composite, eliminating the need for separate coating equipment. The barrier layer is formed during the same manufacturing process as the PET layers, using standard injection molding or blow molding equipment.

Inventive Principle:
Principle #40Composite materials

4Reliability

If multi-layered containers with high barrier material are used, then gas barrier properties are improved, but delamination occurs impacting appearance and performance

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidlayer adhesion
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses 2,5-furandicarboxylate polyester as the barrier material, which has chemical structure similarities to PET (both are polyesters). This structural homogeneity promotes excellent interlayer adhesion and compatibility, preventing delamination while providing superior gas barrier properties.

Inventive Principle:
Principle #33Homogeneity

5Reliability

If barrier enhancement additive is blended into PET and sandwiched between PET layers, then gas barrier properties are improved, but plasticization occurs impacting mechanical properties

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses 2,5-furandicarboxylate polyester which is chemically compatible with PET (both polyesters with similar structures). This compatibility prevents plasticization and maintains mechanical properties while achieving gas barrier enhancement through the multilayer configuration.

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 multilayer structure provides improved CO2 and O2 barrier performance, maintaining mechanical stability and clarity, with a barrier improvement factor of up to 2.0, suitable for packaging carbonated and oxygen-sensitive beverages.

Implementation Method 1

the relative susceptibility of PET to permeation by oxygen and carbon dioxide limits its application

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3256320B1Barrier enhanced pet multilayer container
Publication Date: 2025.07.09 THE COCA COLA CO
  • EP3256320B1 patent drawingFigure 1
  • EP3256320B1 patent drawingFigure 2
  • EP3256320B1 patent drawing

AI summary

This disclosure provide new multilayer polyester (particularly PET) containers that have improved gas barrier properties over conventional monolayer PET containers. In particular, a 2,5-furandicarboxylate polyester (for example, poly(ethylene furan-2,5-dicarboxylate) (PEF)) barrier layer that has superior gas barrier and mechanical properties relative to PET, that is "sandwiched" between two PET layers, has been found to achieve a significantly higher barrier against gas permeation relative to conventional monolayer PET container of the same size and shape. Associated preforms, methods, and compositions are disclosed.