Vulcanized EPDM Profile Strip with Embedded UHMWPE Particles
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Solution Overview
Problem
Existing profile strips for motor vehicles face challenges in maintaining low friction and dimensional stability in hot molds, particularly when using thermoplastic anti-friction coatings with embedded sliding particles, which can melt or degrade during injection molding processes, affecting optical and functional properties.
Innovation Solution
A profile strip with a vulcanized EPDM matrix and co-extruded anti-friction coating, where the EPDM matrix includes ultra-high molecular weight polyethylene (UHMW-PE) sliding particles, ensuring low friction and thermal stability, and allowing for the integration of additional sealing features made from EPDM injection molding material without degrading the anti-friction coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thermoplastic anti-friction coating with embedded sliding particles is applied to a sealing profile section, then low friction is achieved, but the coating melts or degrades during injection molding processes
Solution Approach 1:
The patent changes the material parameter from thermoplastic to thermosetting rubber (EPDM), which fundamentally alters the thermal behavior. The crosslinking process transforms the material from meltable to thermally stable, allowing it to withstand injection molding temperatures without deforming while maintaining the low-friction sliding particles embedded within.
Solution Approach 2:
The patent creates a composite material system combining thermosetting rubber (EPDM) with thermoplastic sliding particles (UHMW-PE). This composite structure allows the matrix material to provide thermal stability during molding while the embedded sliding particles maintain their low-friction properties, resolving the contradiction between ease of operation and reliability in hot conditions.
2Ease of operation
If a sliding coating is applied to a sealing profile section, then low friction is achieved, but separate process steps are required and adhesion is generally not satisfactory
Solution Approach 1:
The patent merges the sliding coating application with the sealing profile manufacturing into a single co-extrusion process. The sliding particles are incorporated into the EPDM compound before extrusion, eliminating separate coating steps and improving adhesion through intimate mixing at the molecular level during the vulcanization process.
Solution Approach 2:
The sliding particles are pre-mixed into the EPDM compound before extrusion and vulcanization. This preliminary incorporation ensures uniform distribution and strong adhesion from the outset, avoiding the need for subsequent coating applications and ensuring the sliding properties are integral to the profile structure.
3Reliability
If a sliding coating with good dimensional stability in hot molds is applied, then thermal stability is achieved, but adhesion to the sealing profile section is generally not satisfactory
Solution Approach 1:
The patent creates a homogeneous composite where sliding particles are distributed throughout the EPDM matrix at the molecular level during compounding. This intimate mixing ensures both strong adhesion (as the particles are part of the matrix structure) and thermal stability (as the crosslinked EPDM resists deformation), eliminating the adhesion problems of surface-applied coatings.
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 excellent adhesion, longevity, and noise reduction with high abrasion resistance, maintaining the essential properties of the sliding particles even when molded with additional features, while being cost-effective and thermally stable.
Implementation Method 1
sliding particles embedded in the anti-friction coating matrix, which are made of UHWM-PE (ultra-high molecular weight polyethylene)... a very low coefficient of friction can be present between the contact surface and the part of the motor vehicle
Implementation Method 2
the anti-friction coating matrix is a vulcanized EPDM matrix... The elastic properties of EPDM are superior to those of thermoplastic elastomers... high resistance to chemicals, UV radiation and weather influences
Implementation Method 3
the sealing profile section and the anti-friction coating are co-extruded... for co-extruding the rubber and the EPDM material, so that a profile strand with a sealing profile section from the rubber material and a sliding coating is formed
Data Source
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AI summary
The invention relates to a profile strip (26) for a motor vehicle (10), in particular for a sealing assembly (24) in a window or door region of a motor vehicle (10), comprising a securing profile section (28) that can be fixed in a first part (20) of the motor vehicle (10), and a sealing profile section (30) connected to the securing profile section (28), produced from a vulcanised rubber matrix and designed to permit relative movements with reduced friction between the profile strip (26) and a second part (16) of the motor vehicle (10), wherein a contact surface (32) of the sealing profile section (30) that can be brought into contact with the second part (16) is provided with an anti-friction coating (34) having an anti-friction coating matrix (36) and anti-friction particles (38) embedded in the anti-friction coating matrix (36), produced from UHMWPE. In addition, the anti-friction coating matrix (36) is a vulcanised EPDM matrix.