Micro-cellular foam weather seal co-extrusion

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Solution Overview

Problem

Existing weather seals for windows and doors are costly, complex to produce, and require multiple materials and extruders, making them environmentally unfriendly and difficult to recycle.

Innovation Solution

A micro-cellular foam weather seal made from thermoplastic elastomers with a chemical foaming agent, combined with a polypropylene spine and barbs, which can be produced using a single-step co-extrusion process with two or three conventional extruders, and optionally includes a silicone slip agent for reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple materials and extruders are used to produce advanced weather seals with foam filled centers, then the sealing performance and resilience are improved, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple materials (thermoplastic elastomer and foam filling material) into a single co-extrusion process using one extruder, eliminating the need for multiple separate extrusion steps and multiple extruders. This merging of materials and processes reduces manufacturing complexity while maintaining the multi-material construction needed for reliable sealing performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single extruder system is designed to handle multiple materials simultaneously, making the extrusion process universal for producing complex multi-material weather seals. The co-extrusion capability allows one piece of equipment to perform what previously required multiple specialized extruders, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple extruders are used to produce foam filled weather seals, then the material diversity and sealing capability are improved, but the production cost and space requirements increase

Engineering Contradiction:
Improvematerial diversityVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple material feeding systems into a single extruder that can process both thermoplastic elastomer and foam filling material simultaneously. This consolidation reduces the number of extruders from three or more to just one, significantly lowering production costs and space requirements while maintaining the ability to produce diverse material combinations.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional foam filling processes are used, then the sealing resilience is improved, but the recyclability and environmental friendliness deteriorate

Engineering Contradiction:
Improvesealing resilienceVSAvoidrecyclability
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state and processing parameters of the foam filling material by incorporating it directly into the extrusion process rather than filling it separately. This parameter change allows the foam material to be integrated with the thermoplastic elastomer in a way that maintains sealing resilience while improving recyclability, as the integrated structure allows for more efficient material recovery and reprocessing.

Inventive Principle:
Principle #35Parameter changes

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 a cost-effective, resilient, and recyclable weather seal with low closing force and minimal loss of functional height over time, while reducing production complexity and environmental impact.

Implementation Method 1

made from thermoplastic elastomers with a chemical foaming agent

Methodology Applied
Scientific EffectChemical foaming: Foam

Implementation Method 2

optionally includes a silicone slip agent for reduced friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3973133B1Micro-cellular foam weather seal
Publication Date: 2025.05.14 ULTRAFAB INC
  • EP3973133B1 patent drawingFigure 1~2
  • EP3973133B1 patent drawingFigure 3
  • EP3973133B1 patent drawingFigure 4

AI summary

A weather seal includes an elongated micro-cellular foam bulb, and an elongated micro- cellular foam fin element attached to and extending along the length of the foam bulb. The fin element includes a spine having opposed planar surfaces and at least one microcellular foam barb extending outwardly and at a downward angle from each surface and along the length of the spine. As an alternative to barbs, another option is to use a higher durometer foamed thermoplastic elastomer in a hollow circle shape that would push into a retention pocket. A t-slot version that has a foamed bulb and a polypropylene base is another option.