Multilayer EVOH Tube Structure for Thin-Wall Barrier Packaging
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Solution Overview
Problem
Plastic tubes used for containing liquid or pasty products face issues with diffusion of volatile components, leading to product degradation and reduced effectiveness, while efforts to reduce weight for environmental impact make them unstable.
Innovation Solution
A multi-layer tube design with a barrier layer made of ethylene-vinyl alcohol copolymer (EVOH) having an ethylene content of < 28 mol% and a thickness ≤ 25 µm, combined with adhesion promoter layers, ensures both lightweight stability and effective barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the tube jacket is made thinner to reduce weight, then weight and environmental impact are reduced, but the tube becomes unstable and barrier properties deteriorate
Solution Approach 1:
The tube jacket uses a multi-layer composite structure combining polyolefin layers with an EVOH barrier layer. This composite design provides superior barrier properties against oxygen and moisture diffusion while maintaining lightweight characteristics, resolving the contradiction between weight reduction and reliability maintenance.
Solution Approach 2:
The barrier layer with specific EVOH composition (ethylene content 22-28 mol%) is strategically positioned between polyolefin layers to provide localized high-performance barrier properties where needed most, while the overall tube structure remains thin and lightweight.
2Weight of moving object
If the barrier layer thickness is reduced to minimize weight, then weight and environmental impact are reduced, but diffusion of volatile components increases
Solution Approach 1:
The EVOH barrier layer is optimized with specific compositional parameters (ethylene content 22-28 mol%) and thickness (5-25 μm) to achieve maximum barrier effectiveness per unit thickness. This parameter optimization provides superior diffusion resistance while minimizing weight, resolving the contradiction between thinness and barrier performance.
Solution Approach 2:
The multi-layer composite structure with EVOH barrier layer provides enhanced diffusion resistance compared to single-layer structures of equivalent weight, allowing thin-wall design while preventing volatile component loss.
3Strength
If adhesion promoter layers are added to improve bonding between barrier layer and polyolefin, then bond strength is improved, but device complexity increases
Solution Approach 1:
Adhesion promoter layers are introduced as intermediary layers between the EVOH barrier layer and polyolefin layers. These promoter layers facilitate strong interfacial bonding that would otherwise be difficult to achieve, ensuring structural integrity of the multi-layer composite while maintaining a relatively simple overall design.
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 design achieves sufficient barrier properties to maintain product integrity for over a year, while minimizing weight and environmental impact, with O2 transmission rates as low as 0.0012 cm³/tube/day.
Implementation Method 1
a barrier layer arranged between the outer layer(s) and the inner layer(s), wherein the barrier layer consists of an ethylene-vinyl alcohol copolymer (EVOH)... sufficient barrier properties to maintain product integrity... O2 transmission rates as low as 0.0012 cm³/tube/day
Implementation Method 2
Since ethylene-vinyl alcohol copolymer does not form a mechanically strong bond with certain polyolefins, it is advantageous or even necessary to provide adhesion promoter layers between the barrier layer and the polyolefin layers
Data Source
AI summary
In a tube for receiving a liquid or pasty product comprising a multilayer tube shell, wherein the tube shell comprises one or more outer layer(s) of polyolefin, one or more inner layer(s) of polyolefin and a barrier layer arranged between the outer layer(s) and the inner layer(s), wherein the barrier layer consists of an ethylene-vinyl alcohol copolymer (EVOH), the ethylene-vinyl alcohol copolymer of the barrier layer has an ethylene content of < 35 mol% and the thickness of the barrier layer is ≤ 25 µm.