Multi-layer Polypropylene Foam Container for Recyclability

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Solution Overview

Problem

Expanded polystyrene containers are challenging to recycle and face public perception issues, leading to bans in municipalities, necessitating a more recyclable and environmentally friendly alternative for thermal insulation in beverage containers.

Innovation Solution

A multi-layer sheet for forming expanded foam containers, comprising a first layer of high melt strength homopolymer or copolymer polypropylene and a second unexpanded layer of high melt strength polypropylene, co-extruded, extrusion coated, or laminated on the first layer, to create a container with improved recyclability and thermal insulation properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If expanded polystyrene is used for container material, then thermal insulation and light weight are achieved, but recyclability deteriorates and public perception becomes negative

Engineering Contradiction:

Improvethermal insulationVSAvoidrecyclability

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining expanded polypropylene foam core with unexpanded polypropylene skin layers to create a multi-layer structure. This composite approach maintains the thermal insulation benefits of expanded foam while incorporating unexpanded layers that improve recyclability and eliminate the public perception issues associated with expanded polystyrene.

Inventive Principle:

Principle #40Composite materials

2Temperature

If expanded polystyrene is used for container material, then thermal insulation is achieved, but environmental friendliness deteriorates

Engineering Contradiction:

Improvethermal insulationVSAvoidenvironmental friendliness

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters by substituting expanded polystyrene with expanded polypropylene. This parameter change maintains the required thermal insulation performance while improving environmental friendliness, as polypropylene is more readily recyclable and has better environmental acceptance than expanded polystyrene.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If multi-layer structure is implemented, then recyclability and environmental friendliness improve, but manufacturing complexity increases

Engineering Contradiction:

ImproverecyclabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent segments the container wall into distinct functional layers: an expanded polypropylene foam core layer for thermal insulation and unexpanded polypropylene skin layers for structural integrity and recyclability. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturability through co-extrusion or lamination processes.

Inventive Principle:

Principle #1Segmentation

4Weight of moving object

If expanded foam material is used, then light weight is achieved, but structural strength may deteriorate

Engineering Contradiction:

Improvelight weightVSAvoidstructural strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent uses composite materials where the expanded polypropylene foam core provides light weight and thermal insulation, while the unexpanded polypropylene skin layers provide structural strength and rigidity. This composite structure achieves both light weight and adequate structural strength for beverage container applications.

Inventive Principle:

Principle #40Composite 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 solution provides containers with equivalent thermal insulation and strength to traditional expanded polystyrene foam while being lighter and more recyclable, addressing the recycling challenges and public perception issues associated with expanded polystyrene.

Implementation Method 1

The unexpanded skin layer can prevent leakage of the expanded core layer

Methodology Applied

Scientific EffectPhysical barrier:

Implementation Method 2

Insulated containers, such as cups, can be used to store hot or cold beverages or food while providing a consumer holding the container with some protection from the temperature of the items stored in the container

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS10059037B2Insulated container and methods of making and assembling

Publication Date: 2018.08.28 DART CONTAINER CORP

AI summary

A multi-layer sheet for forming an expanded foam container, the multi-layer sheet including a first layer of an expanded foam material including a first polyolefin-based material including at least one polypropylene-based polymer and a second layer of an unexpected material including a second polyolefin-based material including at least one polypropylene-based polymer that is co-extruded, extrusion coated, or laminated on a first side of the first layer.