In-Mold Labeled Containers with Oxygen Barrier Layers
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Solution Overview
Problem
Current in-mold labeled (IML) containers have insufficient oxygen barrier properties and are not retortable due to thin labels, which are affected by humidity and high temperatures, making them unsuitable for products that need to be isolated from oxygen during storage or retorting.
Innovation Solution
A multilayered label with an oxygen absorbing resin layer containing ethylene-vinyl alcohol copolymer and an oxygen absorbent is set into a mold, and melted resin is injected to form a container with an integrated oxygen barrier layer, ensuring the label covers the entire container surface and providing enhanced oxygen barrier properties while being retortable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin label is used in IML containers, then the manufacturing process is simple and cost-effective, but the oxygen barrier property is insufficient
Solution Approach 1:
The patent applies composite materials by creating a multilayered label structure comprising multiple functional layers: an outer layer, an oxygen barrier layer (with EVOH), an oxygen absorbing resin layer (containing oxygen absorbent and dispersant), and an inner layer. This composite structure combines the benefits of different materials to achieve both adequate thickness for oxygen barrier properties and compatibility with IML manufacturing processes.
Solution Approach 2:
The patent applies local quality by concentrating the oxygen barrier function in a specific layer (the oxygen barrier layer containing EVOH) rather than distributing it throughout the entire label. This allows each layer to have optimized properties for its specific function while maintaining overall label performance.
2Reliability
If the oxygen barrier layer is made thick, then the oxygen barrier property is improved, but the label cannot be produced using available IML methods
Solution Approach 1:
The patent applies segmentation by dividing the thick oxygen barrier requirement into multiple thinner functional layers. Instead of using a single thick layer that cannot be properly formed by IML injection, the oxygen barrier function is segmented across several layers (outer layer, oxygen barrier layer, oxygen absorbing resin layer, inner layer), each with optimized thickness that can be successfully manufactured using standard IML methods.
3Ease of manufacture
If a conventional label is used, then the manufacturing process is simple, but the label is adversely affected by humidity and high temperatures during retorting
Solution Approach 1:
The patent applies composite materials by incorporating an oxygen absorbing resin layer containing an oxygen absorbent and a dispersant within the multilayered structure. This composite composition provides stability under humidity and high temperature conditions by actively managing oxygen levels and preventing degradation of the label and container contents during retorting and storage.
Solution Approach 2:
The patent applies self-service through the oxygen absorbent in the oxygen absorbing resin layer, which automatically absorbs excess oxygen within the label structure without external intervention. This self-regulating mechanism maintains label stability and prevents oxygen-related degradation during exposure to humidity and high temperatures, eliminating the need for additional protective measures.
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 results in IML containers with excellent oxygen barrier properties that can maintain product freshness for extended periods and withstand retorting, effectively preventing oxygen degradation and extending shelf-life.
Implementation Method 1
a multilayered label having an oxygen barrier layer... the multilayered label has at least an oxygen absorbing resin layer containing ethylene-vinyl alcohol copolymer and an oxygen absorbent
Implementation Method 2
injecting a melted resin suitable for forming a container into the mold
Data Source
AI summary
The invention provides novel processes for producing in-mold labeled containers and the containers produced using such processes. The processes involve setting a multilayered label having an oxygen barrier layer into a mold and injecting a melted resin suitable for forming a container into the mold. The process forms a container with an oxygen barrier layer. In preferred embodiments, the multilayered label has at least an oxygen absorbing resin layer containing ethylene-vinyl alcohol copolymer and an oxygen absorbent and the container is retortable.