Multilayer Bottle Barrier Layer Delamination Prevention
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Solution Overview
Problem
Multilayer bottles with good gas-barrier properties often suffer from delamination issues when exposed to impact or stress, and existing solutions compromise either the gas-barrier performance or increase production costs.
Innovation Solution
A multilayer bottle design featuring a thermoplastic polyester resin for the outermost and innermost layers, with a barrier layer composed of a polyamide obtained by polycondensing m-xylylenediamine and an α,ω-linear aliphatic dicarboxylic acid, blended with a polyamide having higher saturation water content to enhance interlaminar bonding strength and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyamide MXD6 is used as the barrier layer resin to achieve good gas-barrier property, then oxygen-barrier property is improved, but the bottle undergoes delamination between layers when exposed to impact
Solution Approach 1:
The patent uses a composite resin composition for the barrier layer consisting of polyamide MXD6 (60-90 wt%) blended with polyethylene terephthalate (PET) (10-40 wt%). This composite approach maintains the excellent gas-barrier properties of polyamide MXD6 while incorporating PET to improve interlaminar bonding strength and delamination resistance, resolving the contradiction between barrier performance and layer adhesion.
2Strength
If nylon 6 and nylon 6I/6T are added to polyamide MXD6 to prevent crystallization and improve delamination resistance, then delamination resistance is improved, but gas-barrier property deteriorates
Solution Approach 1:
Instead of using expensive polyamides like nylon 6 and nylon 6I/6T that compromise gas-barrier properties, the patent employs polyethylene terephthalate (PET) as a cost-effective alternative additive in the barrier layer. PET effectively prevents crystallization of polyamide MXD6 and improves delamination resistance while maintaining excellent gas-barrier properties, providing a more economical and performance-preserving solution.
3Reliability
If transition metal-based catalyst is added to compensate for poor oxygen-barrier property, then oxygen-barrier property is improved, but production cost increases
Solution Approach 1:
The patent eliminates the need for expensive transition metal-based catalysts by using a composite resin system of polyamide MXD6 blended with PET in the barrier layer. This composition inherently provides excellent oxygen-barrier properties without requiring additional catalytic additives, thereby maintaining high barrier performance while significantly reducing production costs.
4Strength
If multilayer bottle is formed into shape with less irregularities and less bends to prevent delamination, then delamination resistance is improved, but design freedom is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the barrier layer by using a composite resin system of polyamide MXD6 (60-90 wt%) and PET (10-40 wt%). This compositional modification fundamentally improves interlaminar bonding strength and delamination resistance, allowing the bottle to maintain excellent delamination resistance across various shapes, sizes, and designs without being constrained to specific geometric forms.
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 effectively prevents delamination while maintaining excellent gas-barrier properties and reducing production costs, allowing for a wider range of bottle designs without specific shape constraints.
Implementation Method 1
the barrier layer includes a polyamide (B) obtained by polycondensing a diamine component containing 70 mol % or more of m-xylylenediamine with a dicarboxylic acid component containing 70 mol % or more of an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and a polyamide (C) having a higher saturation water content than that of the polyamide (B)
Data Source
AI summary
There is provided a multilayer bottle including outermost and innermost layers each made mainly of a polyester (A) and at least one barrier layer interposed between the outermost and innermost layers. The polyester (A) is a thermoplastic resin obtained by polymerizing a dicarboxylic acid component containing 80 mol % or more of terephthalic acid with a diol component containing 80 mol % or more of ethylene glycol. The barrier layer is composed of a polyamide (B) and a polyamide (C). The polyamide (B) is obtained by polycondensing a diamine component containing 70 mol % or more of m-xylylenediamine with a dicarboxylic acid component containing 70 mol % or more of an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The polyamide (C) has a higher saturation water content than that of the polyamide (B) as measured at 23° C. and 50% RH under 1 atm, and a content of the polyamide (C) in the barrier layer is 20% by weight or less on the basis of a weight of the barrier layer. The multilayer bottle hardly suffers from delamination upon dropping or upon exposure to impact and, therefore, is not required to have a shape with less irregularities or less bends for preventing the delamination, and further has a large freedom of design choice.