EPDM Sealing Strip Welding via Phase Transition

Solution Overview

Problem

Conventional sealing profiles for windows and doors face issues with gluing requirements adding costs and potential gaps due to shrinkage over time, as elastomer profiles cannot be welded due to cross-linking, while thermoplastic seals have drawbacks in cost, processability, and service life.

Innovation Solution

A material mixture comprising EPDM, copolymer, filler, and paraffinic oil, which transitions from a non-crosslinked to a deformable and then crosslinked state, allowing welding without melting, enabling identical processing methods to elastomeric products and maintaining dimensional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastomer sealing profiles are used, then durability and elasticity are improved, but welding is not possible due to cross-linking

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies the dynamics principle by creating a sealing profile that dynamically changes its state between thermoplastic and elastomeric properties. The material transitions from a crosslinked elastomeric state (for durability) to a thermoplastic state (for welding) and back again, enabling both welding and long-term reliability through state transformation rather than static material properties

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent utilizes phase transitions by heating the sealing profile to melt the thermoplastic copolymer phase, enabling welding, then cooling and re-crosslinking to restore elastomeric properties. This phase transition between thermoplastic and elastomeric states allows the material to exhibit different properties at different stages of the manufacturing and service process

Inventive Principle:

Principle #36Phase transitions

2Ease of manufacture

If thermoplastic seals are used, then welding is enabled, but service life and processability deteriorate

Engineering Contradiction:

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite materials by combining two distinct polymer systems: a crosslinked elastomeric base (EPDM) providing durability and elasticity, and a thermoplastic copolymer (polyolefin) providing weldability. This composite structure allows the sealing profile to exhibit both elastomeric longevity and thermoplastic processability, resolving the contradiction between service life and ease of manufacture

Inventive Principle:

Principle #40Composite materials

3Strength

If gluing is used to join sealing profiles, then connection is achieved, but additional work steps and costs increase

Engineering Contradiction:

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent applies the merging principle by integrating the welding capability directly into the sealing profile material itself, allowing the joining operation to be combined with the shaping operation. The sealing profile can be extruded and welded in one continuous process, eliminating the need for separate gluing steps and thereby improving productivity while maintaining connection strength

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If sealing profiles are not glued, then manufacturing is simpler, but gaps form due to shrinkage over time

Engineering Contradiction:

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-crosslinking the elastomeric EPDM base material before extrusion, establishing a stable dimensional framework that prevents shrinkage. This preliminary crosslinking ensures that the sealing profile maintains its dimensions and sealing performance over time, even without post-installation gluing, thereby preserving both manufacturing efficiency and reliability

Inventive Principle:

Principle #10Preliminary action

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

Enables cost-effective, one-operation welding of sealing profiles with elastomeric products, enhancing durability and reducing operational costs by maintaining dimensional stability and elasticity.

Implementation Method 1

The copolymer can melt when heated/welded

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

Crosslinking is advantageously carried out after shaping, expediently by the action of temperature (similar to elastomers)

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

the material mixture remains dimensionally stable at higher temperatures

Methodology Applied

Scientific EffectThermal stability: Thermal Expansion

Data Source

PatentEP2805807B1Sealing strip of EPDM, ethylene-propylene copolymer and sulfur for seals of doors and windows

Publication Date: 2017.10.11

AI summary

Sealing profile, in particular for windows and doors, made of a material mixture comprising an elastomer component and an additive, characterized in that the material mixture has a first state in which the elastomer component is uncrosslinked, and that the material mixture has a second state in which the material mixture is deformable and/or deformed, and that the material mixture has a third state in which the material mixture is crosslinked, wherein the third state is present after the second state.