Molded Surface Fastener with Magnetic Engaging Elements
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Solution Overview
Problem
Molded surface fasteners with hook-shaped engaging elements require practical rigidity and attraction force to magnets while preventing breakage during attachment and detachment, but existing thermoplastic polymers degrade with moisture and lack sufficient rigidity, and co-extrusion molding of different resin compositions is challenging due to fluidity differences.
Innovation Solution
A resin composition combining thermoplastic polyester and thermoplastic polyester elastomer with a magnetic material, where the substrate portion is made of thermoplastic polyester and the engaging elements are made of a composition with a high content of thermoplastic polyester elastomer and magnetic material, allowing for co-extrusion molding and improved toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoplastic polyester is used for the substrate portion, then practical rigidity is achieved, but attraction force to magnets is insufficient
Solution Approach 1:
The surface fastener is divided into two distinct portions with different material compositions: the substrate portion uses thermoplastic polyester for rigidity, while the engaging elements use a magnetic resin composition for attraction force. This segmentation allows each part to optimize its material properties independently, resolving the contradiction between rigidity and magnetic attraction.
Solution Approach 2:
Different regions of the surface fastener are assigned different material properties tailored to their specific functions. The substrate portion requires rigidity and is made of non-magnetic thermoplastic polyester, while the engaging elements require magnetic properties and are made of magnetic resin composition. This local differentiation of material quality resolves the contradiction by providing each region with exactly the properties it needs.
2Force
If magnetic material is incorporated into the resin composition, then attraction force to magnets is improved, but toughness decreases and breakage occurs during handling
Solution Approach 1:
The magnetic material is segregated to only the engaging elements portion, while the substrate portion remains free of magnetic materials. This segmentation ensures that the engaging elements have sufficient magnetic attraction force without compromising the overall toughness of the fastener, as the non-magnetic substrate provides structural support.
Solution Approach 2:
Magnetic properties are localized to the engaging elements where they are functionally required, while the substrate maintains non-magnetic composition for optimal mechanical properties. This local quality differentiation allows the engaging elements to achieve high attraction force without the entire fastener suffering from reduced toughness.
3Strength
If different resin compositions are used for substrate portion and engaging elements, then optimal properties for each part are achieved, but co-extrusion molding becomes difficult due to fluidity differences
Solution Approach 1:
The resin compositions for both the substrate portion and engaging elements are formulated to have comparable melt viscosity and fluidity characteristics during processing. By adjusting parameters such as molecular weight, additives, and composition ratios, both resins can be co-extruded simultaneously without one resin dominating or preventing proper molding, thus enabling the manufacture of multi-material fasteners with optimal properties.
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 molded surface fastener with enhanced toughness and attraction force to magnets, preventing breakage during handling, while maintaining practical rigidity and reducing material costs through efficient co-extrusion molding.
Implementation Method 1
fixing the surface fastener by attraction force between this magnetic material and magnets 123 placed within the mold 121
Data Source
AI summary
An integrally moldable molded surface fastener retains practical rigidity, while having attraction force to a magnet and is prevented from being easily broken during attachment and detachment handlings to and from loop-shaped engaging elements. A first resin composition including 80% by mass or more of a thermoplastic polyester and containing no magnetic material is used in at least a part of a substrate portion, and a second resin composition containing a thermoplastic polyester, a thermoplastic polyester elastomer and a magnetic material at a certain proportion is used in at least a part of engaging elements of the molded surface fastener.