Multilayered Plastic Container EVOH Adhesive Layer
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Solution Overview
Problem
Multilayered plastic containers with EVOH copolymer intermediate layers face challenges in achieving excellent oxygen-barrier properties without the need for special adhesive layers, particularly when used with polyolefin resins, as they exhibit poor adhesiveness and require complex layer structures and increased production costs.
Innovation Solution
A multilayered plastic container structure featuring an oxygen-barrier layer of EVOH copolymer as a matrix with an adhesive intermediate layer composed of a blend of EVOH copolymer and MAMO resin, utilizing high and low MFR MAMO resin components in specific ratios to enhance adhesiveness without impairing oxygen-barrier properties, allowing for effective use with polyolefin resin layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an EVOH copolymer intermediate layer is used to achieve excellent oxygen-barrier property, then oxygen-barrier property is improved, but adhesive property to polyolefin resin layers deteriorates causing delamination
Solution Approach 1:
The patent applies composite materials by creating an adhesive intermediate layer that is a blend of EVOH copolymer (providing oxygen-barrier function) and MAMO resin (providing adhesive function). This composite structure allows the layer to simultaneously achieve both excellent oxygen-barrier properties and strong adhesion to polyolefin resin layers, resolving the contradiction between these two properties.
Solution Approach 2:
The patent applies parameter changes by optimizing the composition ratio of EVOH copolymer to MAMO resin in the adhesive intermediate layer, and by controlling the ethylene content of the EVOH copolymer within a specific range (20-60 mol%). These parameter optimizations enable the layer to balance oxygen-barrier performance with adhesive compatibility to polyolefin resins.
2Strength
If adhesive layers are added to improve adhesion between EVOH copolymer and polyolefin resin layers, then adhesive property is improved, but layer structure complexity and production cost increase
Solution Approach 1:
The patent applies merging by combining the adhesive function and oxygen-barrier function into a single adhesive intermediate layer. This layer integrates both EVOH copolymer (for oxygen barrier) and MAMO resin (for adhesion), eliminating the need for separate adhesive layers and simplifying the overall layer structure while maintaining excellent adhesion properties.
Solution Approach 2:
The adhesive intermediate layer exhibits multi-functionality by simultaneously providing oxygen-barrier protection (through EVOH copolymer) and adhesive bonding (through MAMO resin). This universal layer performs multiple functions that would otherwise require separate components, reducing structural complexity and production costs.
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 significantly improves adhesiveness between the oxygen-barrier and adhesive intermediate layers, preventing delamination and maintaining high oxygen-barrier properties, even when polyolefin resins are used for the inner and outer layers, thereby simplifying production conditions and reducing costs.
Implementation Method 1
the adhesive intermediate layer has excellent adhesiveness to the inner and outer layers
Implementation Method 2
the EVOH copolymer has excellent oxygen-barrier property
Data Source
AI summary
[Problems] To provide a multilayered plastic container which exhibits excellent oxygen-barrier property of the ethylene-vinyl alcohol copolymer to a sufficient degree without the need of providing a special adhesive layer, and which, when a polyolefin resin is used to form the inner and outer layers, too, not only permits the ethylene-vinyl alcohol copolymer to be effectively used but also makes it very easy to set the conditions for satisfying predetermined properties.[Means for Solution] A multilayered plastic container comprising an oxygen-barrier layer of an ethylene-vinyl alcohol copolymer that serves as a matrix and an adhesive intermediate layer of a blend of an ethylene-vinyl alcohol copolymer and a maleic anhydride-modified olefin resin neighboring each other between an inner layer and an outer layer, wherein both the ethylene-vinyl alcohol copolymer used for forming said oxygen-barrier layer and the ethylene-vinyl alcohol copolymer used for forming said adhesive intermediate layer have an ethylene content of 20 to 60 mol %; and said adhesive intermediate layer contains said ethylene-vinyl alcohol copolymer and the maleic anhydride-modified olefin resin at a weight ratio of 4:6 to 8:2, and contains, as said maleic anhydride-modified olefin resin, a high MFR component having an MFR at 190° C. of 100 to 500 g/10 min. and a low MFR component having an MFR at 190° C. of 2 to 90 g/10 min.