Multifilament Thread Adhesive With Uniform Coating for Waterproof Sealing
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Solution Overview
Problem
Thread-like adhesive bodies used in electronic devices lack a waterproofing function, which is essential for applications such as mobile phones and smartphones.
Innovation Solution
A thread-like adhesive body with a core material and adhesive, where the standard deviation of lengths in the width direction is 100 µm or less, and the core material is a multifilament thread with four or more filaments, ensuring a deposition amount of 20-80% adhesive and a twist factor of 25-120, using an acrylic adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thread-like adhesive body is made by coating a periphery of a core material with adhesive, then it can conform to complex shapes and be used in limited installation spaces, but it lacks waterproofing function due to gaps and irregularities in the adhesive layer
Solution Approach 1:
The patent applies parameter changes by controlling the standard deviation of the adhesive layer thickness to 100 μm or less. This precise control of the thickness parameter ensures uniform coverage that eliminates gaps, thereby achieving waterproofing functionality while maintaining the thread-like structure's ability to conform to complex shapes
Solution Approach 2:
The patent replaces the conventional coating method with a controlled deposition process that ensures uniform adhesive layer thickness. By substituting the traditional mechanical coating approach with a more precise application method, the patent achieves consistent thickness distribution that prevents water penetration while maintaining manufacturing feasibility
2Reliability
If the adhesive layer is made thicker to ensure coverage, then waterproofing improves, but the thread-like adhesive body loses flexibility and ability to conform to complex shapes
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the adhesive layer thickness parameter, specifically limiting the standard deviation to 100 μm or less. This parameter control ensures that the adhesive layer is uniformly thin enough to maintain flexibility and conformability while being sufficiently continuous to provide waterproofing, eliminating the need for thicker, non-conforming layers
3Ease of manufacture
If the adhesive layer has irregular thickness variations, then manufacturing is easier, but gaps form that allow water penetration
Solution Approach 1:
The patent addresses this contradiction by establishing a specific parameter threshold for adhesive layer uniformity: the standard deviation of thickness must be 100 μm or less. This quantitative requirement balances manufacturing ease with waterproofing performance, providing a clear target for the coating process that ensures gap-free coverage without overly complicating the application method
Data Source
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AI summary
The present invention relates to a thread-like adhesive body, including: a core material; and an adhesive that covers a surface in a longitudinal direction of the core material, in which a standard deviation 3σ of lengths in a width direction of the thread-like adhesive body calculated by the following method is 100 µm or less, and the core material is a multifilament thread having four or more filaments. (Calculation Method): An average value of the lengths in the width direction and the standard deviation 3σ of the lengths in the width direction of the thread-like adhesive body are values calculated by observing the thread-like adhesive body under a microscope, measuring lengths in the width direction at 10 points by an interval of 1 cm in the longitudinal direction, and calculating the average value and the standard deviation 3σ of these values. Note that the length in the width direction of the thread-like adhesive body is a maximum value at each measurement point.