Supported Susceptor Film Adhesive Pattern for Frozen Food Packaging

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Solution Overview

Problem

Microwave heating packages with susceptor films tend to warp or buckle during thaw cycles in freezers due to moisture absorption, and delaminate during heating due to moisture release, leading to undesirable food item displacement.

Innovation Solution

A supported susceptor film with a polymer energy interactive material between a polymer film and a support layer, where the adhesive extends across the support layer in the cross direction to stabilize it during thaw cycles and facilitate moisture venting to prevent delamination during heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If full coverage adhesive is used to join susceptor film to support layer, then warping during thaw cycles is prevented, but delamination during heating occurs due to moisture vapor pressure buildup

Engineering Contradiction:
Improvedimensional stability during thaw cyclesVSAvoidbond integrity during heating
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The adhesive is applied in a patterned manner rather than as full coverage, creating discrete adhesive regions separated by non-adhesive regions. This segmentation allows the structure to maintain stability where adhesive is present while providing vapor escape pathways where adhesive is absent, resolving the contradiction between preventing warping and preventing delamination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the support layer are treated differently: some regions have adhesive applied to provide dimensional stability during thaw cycles, while other regions are left non-adhesive to allow moisture vapor escape during heating. This local differentiation of adhesive presence resolves the conflicting requirements of different areas of the structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If patterned adhesive is used to allow moisture vapor escape, then delamination during heating is prevented, but warping during thaw cycles occurs due to insufficient adhesive coverage

Engineering Contradiction:
Improvebond integrity during heatingVSAvoiddimensional stability during thaw cycles
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The adhesive pattern is segmented into specific regions that provide sufficient coverage for dimensional stability during thaw cycles while leaving gaps for vapor escape. The segmentation strategy balances both requirements rather than prioritizing one over the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive pattern parameters (coverage area, region distribution, gap size) are optimized to achieve the dual function of providing dimensional stability during thaw cycles while enabling vapor escape during heating. By adjusting these parameters, both conflicting requirements are satisfied.

Inventive Principle:
Principle #35Parameter changes

3Power

If supported susceptor film is used for microwave heating, then heating and crisping of food items is achieved, but warping and buckling occur during freezer thaw cycles

Engineering Contradiction:
Improvemicrowave heating capabilityVSAvoidstructural stability during thaw cycles
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The adhesive is applied in specific patterns to different regions of the support layer, providing dimensional stability where needed while maintaining the overall structure's ability to handle thermal and moisture changes during freezer thaw cycles, thus preserving structural stability while maintaining microwave heating capability.

Inventive Principle:
Principle #3Local quality

4Power

If supported susceptor film is used for microwave heating, then heating and crisping of food items is achieved, but delamination and lofting occur during heating due to moisture vapor pressure

Engineering Contradiction:
Improvemicrowave heating capabilityVSAvoidlayer bonding integrity
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The adhesive pattern is segmented to create vapor escape pathways through non-adhesive regions, allowing moisture vapor to escape during microwave heating. This prevents pressure buildup that would cause delamination and lofting, while the adhesive regions maintain sufficient bonding integrity for structural stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions are differentiated: adhesive regions provide bonding integrity to prevent delamination, while non-adhesive regions provide vapor escape pathways. This local differentiation resolves the contradiction between maintaining bond integrity and allowing vapor escape during microwave heating.

Inventive Principle:
Principle #3Local quality

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 stabilizes the package against warping during thaw cycles and prevents delamination during microwave heating, ensuring consistent heating and crisping of food items without unwanted structure lofting.

Implementation Method 1

A susceptor generally comprises a thin layer of microwave energy interactive material that tends to absorb at least a portion of impinging microwave energy and convert it to thermal energy

Methodology Applied
Scientific EffectMicrowave energy absorption and conversion to thermal energy: Dielectric Heating

Implementation Method 2

the adhesive extends across the support layer in the cross direction to stabilize it during thaw cycles

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 3

during heating, the moisture in the support layer and/or adhesive is released as water vapor

Methodology Applied
Scientific EffectEvaporation of moisture: Evaporation

Implementation Method 4

The spaces between the adhered areas are believed to serve as pathways for transporting water vapor away from the structure

Methodology Applied
Scientific EffectVapor transport: Diffusion

Data Source

PatentEP2544558B1Microwave heating package for frozen food items
Publication Date: 2019.08.21 GRAPHIC PACKAGING INTERNATIONAL LLC
  • EP2544558B1 patent drawingFigure 1A~1C
  • EP2544558B1 patent drawingFigure 2~3
  • EP2544558B1 patent drawingFigure 4~5A

AI summary

A microwave energy interactive structure includes a susceptor film comprising microwave energy interactive material on a polymer film, a support layer joined to the microwave energy interactive material, and an adjoining layer joined to the support layer. The adjoining layer comprises a paper-based material having a machine direction and a cross direction. The adjoining layer is joined to the support layer by an adhesive region extending in the cross direction across at least a portion of the adjoining layer.