Polymer Blend Seals for Stretchable Assembly and Stable Weld Seams
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Solution Overview
Problem
Existing sealing materials, particularly polyketones, face challenges with rigidity and limited stretchability, leading to difficulties during assembly due to high deformations and forces required, and the weld seams in injection-molded rotationally symmetrical seals exhibit reduced mechanical stability and potential breakage.
Innovation Solution
A polymer mixture comprising thermoplastic polyketone and thermoplastic polyurethane, specifically designed to enhance mechanical properties by combining hardness and stability with increased elasticity, is used to create sealing rings with improved expansion properties and stability, utilizing injection molding processes that minimize the impact of weld seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pure thermoplastic polyketone is used for seals, then hardness and wear resistance are improved, but elasticity and stretchability deteriorate
Solution Approach 1:
The patent applies composite materials by creating a polymer blend consisting of thermoplastic polyketone (50-95 wt%) and thermoplastic polyurethane (5-50 wt%). This composite approach combines the advantageous properties of both materials: polyketone provides hardness, wear resistance, and extrusion resistance, while polyurethane contributes elasticity and stretchability. The synergistic effect of this composite material resolves the contradiction between hardness and elasticity, enabling seals that are both durable and easy to assemble.
2Stability of the object's composition
If pure thermoplastic polyketone is used for seals, then stability is improved, but assembly capability deteriorates due to high deformation forces required
Solution Approach 1:
The polymer blend composite material combines polyketone's stability with polyurethane's elasticity, reducing the deformation forces needed during assembly while maintaining compositional stability. The polyurethane phase acts as a flexible matrix that accommodates deformation during assembly, preventing material damage while the polyketone phase maintains structural integrity and stability.
3Productivity
If injection molding with point or tunnel gate is used for rotationally symmetrical seals, then productivity is improved, but mechanical stability at confluence points deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the material's mechanical properties through the polymer blend formulation. The addition of thermoplastic polyurethane changes the material's viscosity, elasticity, and flow characteristics during injection molding. These parameter changes allow the material to better accommodate the confluence of flow fronts at weld seams, reducing stress concentration and improving mechanical stability at confluence points while maintaining the productivity benefits of point or tunnel gate injection molding.
Data Source
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AI summary
The invention relates to sealing elements containing a polymer mixture which contains at least one thermoplastic polyketone and at least one thermoplastic polyurethane. Furthermore, the invention relates to methods for producing sealing elements, in particular by means of injection molding methods and polymer mixtures.