Waterproof Adhesive for One-Step Flexible Circuit Sealing
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Solution Overview
Problem
Existing waterproof adhesives fail to effectively prevent water vapor ingress in notebook computer keyboards due to multiple printing steps leading to defects, causing oxidation of metallic circuits and key failure.
Innovation Solution
A single-step process using a waterproof adhesive comprising a pressure-sensitive adhesive and polymer water-absorbing expansion material, combined with a hardening agent and end-capping reagent, is applied to bond a protective layer to a circuit board, providing a sealing effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple repeated printing steps are used in screen printing process, then the adhesive can be applied to bond protective layer to circuit board, but small defects such as narrower lines or residual bubbles occur, weakening the sealing effect
Solution Approach 1:
The patent combines multiple printing steps into a single screen printing operation by formulating an adhesive composition that achieves adequate adhesive strength and sealing effect in one application. This merging of steps eliminates the accumulation of defects from repeated printing while maintaining the necessary bonding performance between the protective layer and circuit board.
2Reliability
If multiple repeated printing steps are used, then adhesive coverage can be achieved, but defects such as narrower lines or residual bubbles occur, leading to water vapor ingress and key failure
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive by incorporating specific components (silane-modified polymer, rubber-modified polymer, silane crosslinking agent) that enable the adhesive to achieve adequate bonding and sealing properties through a single printing step. This parameter change in composition allows one-step printing to produce sufficient adhesive coverage and sealing effect without the defects associated with multiple printing operations.
3Ease of manufacture
If existing waterproof adhesive is used with multiple printing steps, then bonding can be achieved, but process complexity increases and cost burden rises due to key failure
Solution Approach 1:
The patent merges multiple printing operations into a single screen printing step, thereby simplifying the manufacturing process and reducing production time. The specially formulated adhesive composition ensures that one printing step is sufficient to achieve the required adhesive strength and sealing effect, eliminating the need for multiple repeated printing operations and associated drying/curing cycles.
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 adhesive effectively seals the circuit board, preventing water vapor ingress and reducing key failure in notebook computers by simplifying the printing process to one step, thereby lowering costs.
Implementation Method 1
The first agent includes a pressure sensitive adhesive and a polymer water-absorbing expansion material
Data Source
AI summary
A waterproof adhesive suitable for a flexible circuit board is provided. The waterproof adhesive includes a first agent and a second agent. The first agent includes a pressure sensitive adhesive and a polymer water-absorbing expansion material. The second agent includes a hardening agent and an end-capping reagent. The first agent and the second agent are mixed for use. A preparation method and an application method of the waterproof adhesive are further provided.