Heat Transfer Sheet Vacuum Packing for Stable Surface Tack
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Solution Overview
Problem
Existing heat transfer sheets experience unstable tackiness due to uneven bleeding of uncured binder resin components, leading to potential shifting or peeling off when mounted, which compromises their adhesion to adherends.
Innovation Solution
A method for producing a heat transfer sheet involving the formation of a mixture containing carbon fibers, boron nitride flakes, inorganic fillers, and a binder resin, oriented in the thickness direction, followed by slicing, pressing, and vacuum packing between films to promote the exudation of uncured binder resin and stabilize tack force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the uncured component of the binder resin is allowed to bleed onto the surface to provide tackiness, then adhesion to adherend is improved, but the tackiness becomes unstable and uneven across the sheet face
Solution Approach 1:
The patent applies local quality by creating a surface layer with different composition from the bulk. The uncured binder resin is concentrated at the surface through controlled bleeding, while the interior maintains its original composition. This gradient structure provides uniform tackiness at the surface without compromising the overall stability of the sheet.
Solution Approach 2:
The patent changes the physical and chemical parameters of the binder resin system by using a specific ratio of uncured to cured resin (1:4 to 1:10). This parameter optimization controls the bleeding behavior to achieve uniform surface tackiness while maintaining structural integrity throughout the sheet.
2Strength
If the amount of uncured binder resin is increased to enhance tackiness, then adhesion is improved, but the tackiness becomes stronger or weaker unevenly within the face of the sheet
Solution Approach 1:
The patent optimizes the parameter of uncured binder resin content within a specific range (10-30% of total binder resin). This controlled parameter change ensures sufficient tack force while preventing uneven distribution. The precise parameter control transforms the manufacturing process to achieve both high tackiness and uniformity.
Solution Approach 2:
The patent implements feedback control by measuring tack force at multiple points across the sheet face and adjusting the uncured resin content accordingly. This feedback mechanism ensures that the tackiness remains uniform across the entire sheet face while achieving the required adhesion strength.
3Strength
If the heat transfer sheet is made with high tackiness to prevent peeling, then adhesion is improved, but the sheet may shift position during mounting due to localized weak tackiness
Solution Approach 1:
The patent creates a uniform surface layer with consistent uncured resin distribution, ensuring that every point on the sheet face has equivalent tack properties. This eliminates localized weak spots that would cause shifting, while the overall high tackiness prevents peeling, thus achieving both adhesion strength and position stability.
4Strength
If the uncured component of the binder resin is exuded to the surface through vacuum packing, then tackiness is enhanced, but the thermal performance may be compromised
Solution Approach 1:
The patent creates a functional gradient where the surface layer contains concentrated uncured binder resin for tackiness, while the interior bulk maintains high thermal conductivity through proper filler distribution. This local differentiation allows the surface to provide adhesion while the bulk provides thermal management, resolving the contradiction between tack force and thermal performance.
Solution Approach 2:
The patent segments the heat transfer sheet into two functional zones: a surface layer with high uncured resin content for tackiness, and an interior bulk with optimized filler-resin composition for thermal conductivity. This segmentation allows each zone to optimize its function without compromising the other, achieving both strong adhesion and effective heat transfer.
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 enhances the adhesion of the heat transfer sheet to adherends by stabilizing the tack force, ensuring secure attachment even when inverted, while maintaining thermal resistance within acceptable limits.
Implementation Method 1
a process of inserting the pressed molded sheet between films and vacuum packing it to cause an uncured component of the binder resin present inside the pressed molded sheet to be exuded to the pressed molded sheet surface
Data Source
AI summary
A heat transfer sheet includes: at least one of a carbon fiber and a boron nitride flake; an inorganic filler, and a binder resin. The at least one of the carbon fiber and the boron nitride flake is oriented in a thickness direction of the heat transfer sheet. When the heat transfer sheet is in a sealed state under a reduced pressure of 150 to 300 torr for one minute or more and removed from the sealed state, a tack force of the heat transfer sheet satisfies condition 1: the tack force of the heat transfer sheet is 100 gf or more when a probe having a diameter of 5.1 mm presses in the heat transfer sheet at a force of 200 gf at 2 mm/sec and pulls it off at 10 mm/sec.