Heat Transfer Sheet Vacuum Packing for Stable Tack Adhesion
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Solution Overview
Problem
Existing heat transfer sheets experience unstable tackiness due to uneven bleeding of uncured binder resin, leading to potential shifting or peeling when mounted on adherends.
Innovation Solution
A production method involving forming a mixture of carbon fiber, boron nitride flake, and binder resin into a molded body, orienting these components in the thickness direction, slicing, pressing, and vacuum packing between films to promote uniform exudation of the binder resin, ensuring a tack force of 100 gf or more.
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 may become stronger or weaker within a face of the heat transfer sheet
Solution Approach 1:
The patent applies local quality by creating a surface layer with different composition from the bulk. The uncured binder resin component is concentrated at the surface through controlled bleeding, while the interior maintains its original composition. This gradient structure ensures uniform tackiness across the surface while maintaining overall stability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the binder resin system by controlling the bleeding of uncured components. Specific parameters including the ratio of uncured to cured resin, molecular weight distribution, and crosslinking density are adjusted to achieve stable, uniform tackiness across the heat transfer sheet surface.
2Strength
If the amount of uncured component of the binder resin that bleeds is increased to strengthen tackiness, then adhesion is improved, but the heat transfer sheet is likely to shift position or peel off when mounted due to partial weakening of tackiness
Solution Approach 1:
The patent creates a localized concentration of uncured binder resin at the surface layer, distinct from the bulk composition. This surface enrichment provides consistent tack force across the entire contact area, preventing partial weakening that would cause shifting or peeling during mounting operations.
Solution Approach 2:
The patent performs preliminary control of the bleeding process during manufacturing to establish uniform distribution of uncured components before mounting. By pre-establishing consistent tackiness across the surface, the heat transfer sheet maintains position stability during the mounting process without requiring additional corrective measures.
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 stabilizes tackiness, improving adhesion and handling of the heat transfer sheet without compromising thermal performance, ensuring secure attachment to adherends.
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.