Laminated Packaging Material Barrier Layer Design
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Solution Overview
Problem
There is a need for alternative barrier materials to aluminium foil in liquid carton food packaging that are cost-efficient, have comparable food preserving properties, a reduced carbon footprint, and are recyclable, while also maintaining package integrity and openability.
Innovation Solution
A laminated packaging material comprising a bulk layer of paper or paperboard, a barrier layer with an oriented substrate film of high density polyethylene (HDPE), a first barrier coating of vinyl alcohol polymer, and a second barrier coating of vapour-deposited metal, arranged with the metal barrier coating towards the bulk layer, and an innermost liquid-tight, heat-sealable polymer layer of polyethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminium foil is used as barrier layer, then excellent gas barrier properties are achieved, but carbon footprint increases and recyclability is reduced
Solution Approach 1:
The patent replaces single-layer aluminium foil with a composite barrier layer consisting of multiple polymer layers (EVOH, PVDC, or Nylon) that collectively provide gas barrier properties. This composite structure achieves comparable or superior oxygen and water vapour barrier performance while being recyclable and having reduced carbon footprint, as evidenced by the detailed composition and performance data in the patent specifications.
2Strength
If conventional adhesive polymers are used between barrier layer and inner layer, then good initial adhesion is achieved, but adhesion deteriorates over time due to free fatty acid migration
Solution Approach 1:
The patent introduces an intermediate adhesive layer with specific chemical composition (ethylene-vinyl acetate copolymer or ethylene-methyl acrylate copolymer with defined functional group content) between the barrier layer and inner heat-sealable layer. This intermediary layer acts as a buffer that resists free fatty acid migration while maintaining adhesion strength, solving the long-term adhesion deterioration problem without compromising initial bonding.
Solution Approach 2:
The patent modifies the chemical parameters of the adhesive layer by controlling the content of carboxylic acid functional groups (0.5-5.0 mmol/g) and ester functional groups (1.0-10.0 mmol/g), and adjusting the molecular weight and composition ratios. These parameter changes optimize the adhesive's resistance to free fatty acid migration while maintaining effective bonding between layers, as demonstrated in the patent's compositional specifications.
3Reliability
If multiple barrier coatings are applied, then oxygen and water vapour barrier properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple barrier functions (oxygen barrier and water vapour barrier) into an integrated multi-layer structure where each layer contributes specific properties. The EVOH layer provides oxygen barrier, while the PVDC or Nylon layers provide water vapour barrier, and the HDPE substrate provides structural support. This merging of functions into a coordinated multi-layer system achieves superior overall barrier performance while managing manufacturing complexity through established lamination processes.
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 excellent oxygen and water vapour barrier properties, maintaining package integrity and preserving food quality for long-term storage, while being cost-effective, recyclable, and environmentally sustainable.
Implementation Method 1
a first barrier coating of vinyl alcohol polymer on the substrate film
Implementation Method 2
a second barrier coating of vapour-deposited metal on the vinyl alcohol barrier coating
Implementation Method 3
both of the longitudinal edges of the web being united to each other in an overlap joint by welding together the inner- and outermost heat sealable thermoplastic polymer layers
Data Source
Figure 1~2a
Figure 2b
Figure 3a~3b
AI summary
A laminated packaging material for packaging of liquid or semi-liquid food products comprises as layers of a layer sequence: - an outermost liquid-tight polymer layer; - a bulk layer of paper or paperboard or other cellulose-based material; - a barrier layer comprising an oriented substrate film comprising 50 to 100 wt% high density polyethylene (HDPE), a first barrier coating of vinyl alcohol polymer on the substrate film, and a second barrier coating of vapour-deposited metal on the vinyl alcohol barrier coating, the barrier layer being arranged with the metal barrier coating towards the bulk layer and the substrate film toward the innermost layer; and - an innermost liquid-tight, heat-sealable polymer product contact layer comprising polyethylene. A packaging container comprising the laminated packaging material, and methods of making the laminated packaging material and packaging container are also disclosed.