Waterproof fastener stringer and method of producing the same
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Solution Overview
Problem
Waterproof slide fasteners experience high likelihood of 'element-turn' due to repeated operation in chemically severe environments, particularly when lubricants other than recommended are used, leading to rotation of fastener elements on the surface of the fastener tape.
Innovation Solution
A method involving through-holes formed at a constant pitch along the side-edge portion of a fastener tape, followed by plasma or corona treatment to create an activation region, and injection molding of fastener elements to enhance adhesion to the waterproof layer, reducing the occurrence of element-turn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wettability of the surface of the waterproof layer is increased through plasma treatment or corona treatment, then the adhesion energy of fastener element to the waterproof layer is improved, but short shot or burr may occur during injection molding
Solution Approach 1:
The plasma treatment or corona treatment is applied selectively to specific regions of the waterproof layer surface where fastener elements will be attached, rather than treating the entire surface. This localized treatment increases adhesion energy at critical attachment points while avoiding excessive wettability in other areas that could cause injection molding defects such as short shot or burr.
Solution Approach 2:
The plasma treatment or corona treatment is applied to a degree that provides sufficient adhesion energy improvement without over-treating the surface. By controlling the treatment intensity and duration, the patent achieves the minimum necessary increase in surface wettability for adequate adhesion while avoiding the excessive wettability that would cause injection molding quality issues.
2Ease of operation
If lubricant is applied to the rows of fastener elements for improved sliding motion, then the ease of operation is improved, but the occurrence of element-turn is facilitated in chemically severe environments
Solution Approach 1:
The patent introduces an intermediary substance or coating on the fastener elements that provides both lubrication for smooth sliding motion and chemical resistance to prevent element-turn. This intermediary layer acts as a mediator between the conflicting requirements of ease of operation and reliability in chemically severe environments.
Solution Approach 2:
The fastener elements are made from composite materials or coated with composite structures that combine lubricating properties with chemical resistance. The composite structure provides both the low friction needed for easy sliding and the stability required to prevent element-turn in chemically severe environments.
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 method significantly reduces element-turn occurrences, allowing for increased durability and resistance to chemical environments, even under severe conditions.
Implementation Method 1
applying a plasma treatment or corona treatment to the side-edge portion of the fastener tape so as to form an activation region on a surface of the waterproof layer
Implementation Method 2
applying a plasma treatment or corona treatment to the side-edge portion of the fastener tape so as to form an activation region on a surface of the waterproof layer
Implementation Method 3
a melted resin adhering to the activation region and filling the through-hole before solidifying into the fastener element
Data Source
AI summary
Through-holes are formed at a constant pitch along a side-edge portion of a fastener tape where a tape base fabric is covered by a waterproof layer, the through-holes piercing the fastener tape. Plasma treatment or corona treatment is applied to the side-edge portion of the fastener tape so as to form an activation region on a surface of the waterproof layer on one or both sides of the fastener tape. Injection molding of fastener elements is performed to attach the fastener elements to the side-edge portion of the fastener tape. Melted resin adheres to the activation region and fills the through-hole before solidifying into the fastener element.