Prepreg Filler Dispersion for Low Thermal Expansion PCBs
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Solution Overview
Problem
Prepregs using glass fillers and aluminum hydroxide for thermal expansion reduction and flame retardance often exhibit uneven resin flow, leading to poor appearance and drilling processability due to fluidity issues between the filler and hydroxide particles.
Innovation Solution
A prepreg composition with aluminum hydroxide and glass filler, where the hydroxide has a 2.5-4.5 μm particle diameter and glass filler has 1.0-3.0 μm diameter and 50-65% SiO2 content, with a 4:6 to 6:4 ratio, combined with a non-halogenated epoxy resin and phosphorus-containing curing agent, ensures even dispersion and improved fluidity, resulting in enhanced circuit formability and drilling processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If aluminum hydroxide and glass filler are blended to reduce thermal expansion and ensure flame retardance, then thermal expansion coefficient is reduced and flame retardance is improved, but resin fluidity becomes uneven causing stripes at the end part and deteriorated appearance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle diameter of aluminum hydroxide (2.5-4.5 μm) and glass filler (1.0-3.0 μm), and their mixing ratio (4:6 to 6:4). This optimization ensures even dispersion of fillers in the resin, preventing stripe formation while maintaining low thermal expansion coefficient and good flame retardance.
Solution Approach 2:
The patent uses a composite material system combining non-halogenated epoxy resin, aluminum hydroxide, and glass filler. This composite formulation achieves synergistic effects where the epoxy resin provides base properties, aluminum hydroxide provides flame retardance, and glass filler provides thermal expansion control, all while maintaining processability.
2Ease of manufacture
If aluminum hydroxide and glass filler are blended to ensure flame retardance and enhance processability, then flame retardance is improved and processability is enhanced, but fluidity between fillers becomes ununiform reducing drilling processability
Solution Approach 1:
The patent optimizes the particle size parameters of aluminum hydroxide (2.5-4.5 μm) and glass filler (1.0-3.0 μm) to control their interaction with the resin matrix. This parameter optimization ensures uniform fluidity during processing while maintaining excellent drilling processability, resolving the contradiction between ease of manufacture and manufacturing precision.
3Stability of the object's composition
If glass filler is used to reduce thermal expansion coefficient, then thermal expansion is reduced, but resin fluidity becomes uneven causing stripes at the end part
Solution Approach 1:
The patent controls the particle diameter of glass filler within 1.0-3.0 μm and adjusts the mixing ratio with aluminum hydroxide to 4:6 to 6:4. These parameter changes ensure uniform distribution of glass filler in the resin, preventing stripe formation at the end part while maintaining the desired low thermal expansion coefficient.
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 achieves a prepreg with even glass filler dispersion, leading to a metal clad laminated plate with excellent drilling processability and low thermal expansion, suitable for printed wiring boards.
Implementation Method 1
the glass filler is evenly dispersed to ensure a fluidity of the resin
Implementation Method 2
ensure a fluidity of the resin and which makes it possible to obtain a metal clad laminated plate having an excellent circuit formability
Data Source
AI summary
Provided is a prepreg prepared by impregnating a base material with a resin composition, wherein the resin composition contains aluminum hydroxide having an average particle diameter of 2.5 to 4.5 µm and a glass filler having an average particle diameter of 1.0 to 3.0 µm, a specific gravity of 2.3 to 2.6 g/cm3 and a SiO2 content of 50 to 65 % by mass; and a sum of blending amounts of aluminum hydroxide and the glass filler is 30 to 50 % by mass based on a whole amount of solid matters in the resin composition. According to the above prepreg, capable of being obtained is a metal clad laminated plate in which in spite of using an inorganic filler such as silica and the like and aluminum hydroxide in combination, the inorganic filler is evenly dispersed and which is excellent in a processability and has a low thermal expansion coefficient.