Multilaminar Foamed Polymer Wall for Thermal Insulation and Stiffness

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Solution Overview

Problem

Existing foamed polymer articles, such as cups or containers, face challenges in achieving high strength for a given wall thickness and mass, often require multiple materials that are difficult to recycle, and lack adequate thermal insulation and rigidity, particularly in non-round containers and wall-like elements.

Innovation Solution

A method involving a combined blowing agent system of physical and chemical blowing agents is used to form a multilaminar expanded cellular foam structure with specific microstructures, allowing for higher strength and thermal insulation in a single recyclable polymer material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a thick wall is used to create thermal insulation in conventional injection moulding, then thermal insulation is improved, but mass and material usage increase

Engineering Contradiction:
Improvethermal insulationVSAvoidmass
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent introduces a foamed cellular microstructure within the polymer wall, creating a porous material that provides thermal insulation through trapped gas cells while reducing overall density and mass compared to solid polymer of equivalent thickness

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent creates a composite structure combining solid polymer skin layers with a foamed cellular core, achieving both structural integrity from the solid components and thermal insulation from the foam, thereby reducing mass while maintaining insulation performance

Inventive Principle:
Principle #40Composite materials

2Temperature

If a blowing agent is added to create a foamed microstructure, then thermal insulation and mass reduction are improved, but structural strength may be compromised

Engineering Contradiction:
Improvethermal insulationVSAvoidwall strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent applies different structures to different regions of the wall: solid polymer skin layers at the outer surfaces provide strength and structural integrity, while the foamed cellular structure in the core provides thermal insulation, with each region optimized for its specific function

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure combining solid polymer skin layers with a foamed cellular core, achieving both structural integrity from the solid components and thermal insulation from the foam, thereby reducing mass while maintaining insulation performance

Inventive Principle:
Principle #40Composite materials

3Reliability

If multiple materials are used to create functional layers, then performance is improved, but recyclability deteriorates due to difficulty in separation

Engineering Contradiction:
Improvefunctional performanceVSAvoidrecyclability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a single polymer material throughout the entire article, including both the solid skin layers and the foamed cellular core, ensuring homogeneous material composition that simplifies recycling while maintaining differentiated functional properties through structural variation rather than material variation

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentEP4457070B1Moulded polymer article and manufacture thereof
Publication Date: 2025.12.17 BOCKATECH LTD
  • EP4457070B1 patent drawingFigure 1~2
  • EP4457070B1 patent drawingFigure 3A~3C
  • EP4457070B1 patent drawingFigure 4

AI summary

A moulded polymer article comprising a monolithic wall part composed of a polymer, the monolithic wall part comprising a core layer of expanded cellular foam, composed of the polymer, disposed between, and integral with, first and second solid skins, composed of the polymer, wherein the core layer is multilaminar and comprises a first layer of the expanded cellular foam adjacent to the first solid skin, a second layer of the expanded cellular foam adjacent to the second solid skin, and an intermediate layer of the expanded cellular foam which is between, and adjacent to, the first and second layers, wherein the first and second layers comprise a first cellular microstructure comprising closed cells and the intermediate layer comprises a second cellular microstructure comprising cells which have an average aspect ratio between a maximum cell dimension and a minimum cell dimension which is greater than 2:1 and less than 5:1 and wherein in the second cellular microstructure the maximum cell dimension of the cells is oriented in a direction extending between the first and second solid skins.