Foam-Based Phase Change Packaging to Prevent Slumping and Leakage

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Solution Overview

Problem

Existing thermal control devices for shipping and transportation, such as gel-based and ice-based systems, are inefficient due to issues like slumping, sublimation, and leakage, and fail to maintain precise temperature ranges required for temperature-sensitive products like pharmaceuticals and fresh food, leading to potential spoilage and degradation.

Innovation Solution

A foam-based phase change device that incorporates a high-absorbency open-cell phenolic foam with a phase change material, such as a salt solution, within a protective covering, optimizing weight-to-volume characteristics and absorption rates to maintain temperature control over extended periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If gel-based thermal control devices are used, then cooling capacity is provided, but slumping occurs during phase change reducing shape stability

Engineering Contradiction:
Improvecooling capacityVSAvoidshape stability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent uses open-cell foam as a porous substrate to contain the phase change material. The foam structure provides rigidity and shape stability while the open cells allow the phase change material to be absorbed and retained throughout the foam matrix, preventing slumping during phase change transitions.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention creates a composite thermal control device combining foam material with phase change material. The foam provides structural stability and shape maintenance, while the phase change material provides cooling capacity, achieving both requirements simultaneously in a single integrated device.

Inventive Principle:
Principle #40Composite materials

2Temperature

If dry ice blocks are used for thermal control, then low temperature cooling is achieved, but sublimation causes carbon dioxide accumulation and pressure buildup

Engineering Contradiction:
Improvecooling temperatureVSAvoidcarbon dioxide accumulation
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state and composition parameters by using a salt solution as the phase change material instead of solid dry ice. This salt solution can be absorbed into the foam and maintains a stable liquid or solid-liquid mixture state during phase change, eliminating sublimation and carbon dioxide gas generation while providing the required low temperature cooling.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If phase change materials are absorbed into foam using vacuum and greater-than-atmospheric pressure, then absorption completeness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveabsorption completenessVSAvoidmanufacturing complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-forming the open-cell foam structure with appropriate pore size and distribution before introducing the phase change material. This pre-prepared foam structure naturally facilitates complete absorption through capillary action when the phase change material is introduced, eliminating the need for complex vacuum and pressure cycling equipment during manufacturing.

Inventive Principle:
Principle #10Preliminary action

4Weight of moving object

If open cell foam is used as absorbing medium, then weight-to-volume characteristics are optimized, but absorption rate may be insufficient without proper pore structure

Engineering Contradiction:
Improveweight-to-volume ratioVSAvoidabsorption rate
Core Design Contradiction:
Weight of moving objectVSSpeed

Solution Approach 1:

The patent specifies open-cell foam with controlled pore size and structure that balances low density (for optimal weight-to-volume characteristics) with sufficient capillary action (for adequate absorption rate). The interconnected open cells provide both lightweight structure and efficient fluid transport pathways for the phase change material.

Inventive Principle:
Principle #31Porous materials

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 foam-based phase change device provides improved cooling efficiency, longevity, and precise temperature control, minimizing weight and shipping costs while preventing leakage and slumping, effectively maintaining the desired temperature range for sensitive products during transport.

Implementation Method 1

Phase change materials are known in the art as materials which use changes in physical phase to absorb or release heat at a relatively constant temperature. Typically, phase change materials undergo the physical transformation known as fusion (freezing / melting), which carries an associated latent heat.

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

Typically, phase change materials undergo the physical transformation known as fusion (freezing / melting), which carries an associated latent heat.

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 3

For some phase change materials a porous substrate has been used as an absorbing and carrying medium.

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2488807B1Thermally-controlled packaging device and method of making
Publication Date: 2020.04.08 SONOCO DEVELOPMENT INC
  • EP2488807B1 patent drawingFigure 1a~1d
  • EP2488807B1 patent drawingFigure 1e
  • EP2488807B1 patent drawingFigure 2a

AI summary

A phase change device for controlling temperature within a confined environment, comprising a foam material, a phase change material, the phase change material being absorbed into the foam, and a protective covering encasing the foam material / phase change material. A method for making a phase change device for controlling temperature within a confined environment, comprising providing a phase change material, providing a foam material, absorbing the phase change material into the foam material, and sealing the foam material / phase change material within a protective covering.