Surface-Treated Filler for Thermal Conductivity
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Solution Overview
Problem
Existing methods for surface-treating fillers to enhance thermal conductivity face challenges such as slow reactivity, difficulty in synthesis, and issues with filler compatibility and hardness adjustment, particularly with dimethylpolysiloxane-based treatments, which require high temperatures and long stirring times, and result in contamination and degradation at high temperatures.
Innovation Solution
A surface-treated filler using α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane with a weight average molecular weight of 500 to 5,000, applied through a method involving a treatment liquid production step, pre-treatment, heat treatment, and drying, to achieve high adhesion percentages and improved thermal conductivity while maintaining moderate hardness and low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If long-chain alkylsilane is used as surface treatment agent, then filling properties are improved, but reactivity becomes slow and synthesis becomes difficult
Solution Approach 1:
The patent changes the molecular structure parameters of the silane coupling agent by introducing a polydimethylsiloxane backbone with controlled molecular weight (500-5000) and specific end groups (α-butyl and ω-(2-trimethoxysilylethyl)). This structural modification maintains the hydrophobicity needed for good filling properties while the controlled molecular weight and end groups provide adequate reactivity, resolving the contradiction between filling properties and reactivity.
Solution Approach 2:
The patent creates a composite surface treatment agent combining polydimethylsiloxane backbone with trimethoxysilyl end groups. This composite structure integrates the benefits of long-chain alkylsilane (hydrophobicity and filling properties) with the reactivity of shorter-chain silanes, achieving both improved filling properties and maintained reactivity simultaneously.
2Adaptability or versatility
If trialkoxysilyl group is used at end of polysiloxane chain, then compatibility with silicone is improved, but reactivity becomes poor and high temperature stirring is required
Solution Approach 1:
The patent optimizes the molecular weight parameter of polydimethylsiloxane to 500-5000 and modifies the end groups to α-butyl and ω-(2-trimethoxysilylethyl). This parameter optimization maintains compatibility with silicone through appropriate hydrophobicity while the specific end groups provide sufficient reactivity even at moderate temperatures, eliminating the need for high temperature stirring.
3Adaptability or versatility
If number of carbon atoms in hydrophobic group is increased, then compatibility with elastomer is improved, but hydrolysis becomes difficult and unreacted silane remains
Solution Approach 1:
The patent controls the number of carbon atoms in the hydrophobic group (α-butyl and ethyl trimethoxysilylethyl) to an optimal range that provides sufficient compatibility with elastomer while maintaining hydrolyzability. The polydimethylsiloxane backbone with controlled molecular weight further enhances this balance, allowing adequate compatibility without excessive hydrophobicity that would prevent hydrolysis.
4Ease of manufacture
If unreacted silane coupling agent remains in polymer system, then filling properties are improved, but contamination and heat resistance deterioration occur
Solution Approach 1:
The patent modifies the molecular weight parameter to 500-5000 and the end groups to α-butyl and ω-(2-trimethoxysilylethyl), creating a silane coupling agent that reacts completely under standard processing conditions. This parameter optimization ensures full reaction of the silane groups, eliminating unreacted silane that would cause contamination and heat resistance deterioration, while maintaining excellent filling properties.
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 solution enables a surface-treated filler that can be highly filled in polymer components, achieving high thermal conductivity and appropriate hardness with a simpler production method, reducing viscosity and improving thermal stability.
Implementation Method 1
α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane having a weight average molecular weight of 500 to 5,000
Implementation Method 2
adhesion percentage of the α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane to the filler is from 20.0 to 50.0% by mass
Implementation Method 3
heat treatment step of heat-treating the mixture obtained in the pre-treatment step at a temperature of from 140 to 180° C.
Data Source
AI summary
A surface-treated filler obtained by surface-treating a surface of a filler with α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane having a weight average molecular weight of 500 to 5,000, wherein an adhesion percentage of the α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane to the filler is from 20.0 to 50.0% by mass.