Dual-ovenable Paper Laminate Container Wrinkle-Free Sealing
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Solution Overview
Problem
Conventional dual-ovenable containers formed from paper-based laminates face issues with wrinkles in deep containers, which interfere with sealing, and existing solutions are not suitable for all configurations, especially when the container depth exceeds its diameter.
Innovation Solution
A dual-ovenable container formed from a laminate blank with a paperboard layer sandwiched by heat-sealable cellophane layers, wrapped into a tubular or conical configuration, and heat-sealed to create a container body with end closures, ensuring structural rigidity, low oxygen permeability, and hermetic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If thermoforming or stamping is used to form paper-based laminate containers, then shallow container configurations can be manufactured effectively, but deep container configurations develop wrinkles in the walls that interfere with sealing
Solution Approach 1:
The patent changes the forming method from thermoforming/stamping to a wrap-around construction method where a flat laminate blank is wrapped around a conical or cylindrical mandrel and heat-sealed. This parameter change in the manufacturing process eliminates wrinkle formation while enabling deep container configurations with depth-to-diameter ratios greater than 0.5, resolving the contradiction between container depth and manufacturing precision.
2Strength
If paperboard layers are used for structural rigidity, then container strength is improved, but oxygen permeability increases
Solution Approach 1:
The patent creates a composite laminate structure consisting of a paperboard layer sandwiched between two heat-sealable cellophane layers. The paperboard provides structural rigidity and strength, while the cellophane layers provide oxygen barrier properties with permeability not greater than 1 cc/100 in 2/24 hr at 0% relative humidity. This composite material approach resolves the contradiction between strength and oxygen permeability by combining materials with complementary properties.
Solution Approach 2:
The patent applies different material properties to different layers of the container wall: the inner and outer cellophane layers provide oxygen barrier functionality, while the intermediate paperboard layer provides structural rigidity. This local differentiation of material qualities allows each layer to optimize its specific function, resolving the contradiction between strength and oxygen permeability.
3Reliability
If the laminate is heat-sealed to form the container body, then hermetic sealing is achieved, but the sealing effectiveness deteriorates when wrinkles are present in deep containers
Solution Approach 1:
The patent performs preliminary smoothing of the laminate blank before wrapping and heat-sealing. The flat blank is carefully wrapped around the mandrel in a controlled manner that prevents wrinkle formation during the forming process. This preliminary action ensures that the subsequent heat-sealing operation can achieve effective hermetic sealing, resolving the contradiction between sealing reliability and container depth.
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 allows for deep containers without wrinkles, maintaining integrity in both conventional and microwave ovens, and provides a high oxygen barrier, enabling extended storage of food without oxidative degradation.
Implementation Method 1
a pair of heat-sealable cellophane layers laminated to and sandwiching the paperboard layer therebetween
Implementation Method 2
Each of the cellophane layers of the blank provides a barrier function such that the laminate has an oxygen permeability not greater than 1 cc/100 in 2
Data Source
Figure 1~6
AI summary
A dual-ovenable container is formed from a blank of laminate material that includes a paperboard layer sandwiched between outer heat-sealable layers of amorphous polyester or heat-sealable cellophane. The blank is wrapped into a tubular or conical configuration and opposite edges of the blank form a lap joint at which the edges are heat-sealed together to form a container body. End closures can then be applied to the ends of the container body. The laminate is heat-sealable to itself, is able to withstand heating/cooking conditions in both conventional and microwave ovens, and has a low oxygen permeability. The edge of the blank exposed to contents of the container can be wrapped by a sideseam tape in order to protect the edge.