Flame-Retarded Resin Composition for Low-Loss PCB Laminates
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Solution Overview
Problem
Existing copper-clad laminates face challenges in achieving low dielectric loss, high glass transition temperature, and high thermal stability while maintaining flame retardancy, due to the negative effects of conventional flame retardants on electrical properties and thermal resistance.
Innovation Solution
A thermosetting resin composition incorporating 4-vinylbenzyl diphenylphosphine oxide with vinyl-terminated PPO resin, which is cured without maleimide, resulting in a composite material with low thermal expansion, high heat resistance, and low dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flame retardants are added to achieve flame retardancy, then flame resistance is improved, but electrical properties and thermal resistance deteriorate
Solution Approach 1:
The invention changes the chemical structure parameters of the flame retardant by introducing a vinyl group that enables radical polymerization. This structural modification allows the flame retardant to become part of the crosslinked network, eliminating the need for high melting points and improving compatibility with the resin system, thereby maintaining electrical properties while achieving flame retardancy
Solution Approach 2:
The invention creates a composite material system where the vinyl-containing phosphine oxide flame retardant is chemically bonded within the crosslinked resin network. This composite structure integrates the flame retardant at the molecular level, ensuring uniform distribution and compatibility while maintaining the resin's electrical and thermal properties
2Temperature
If additive flame retardants with high melting points are used to avoid lowering Tg, then thermal stability is improved, but dispersibility in varnish deteriorates
Solution Approach 1:
The invention changes the physical state parameter of the flame retardant from solid additive to liquid monomer through the introduction of the vinyl group. This allows the flame retardant to be easily dispersed in the varnish without requiring milling, and subsequently incorporates into the crosslinked network, eliminating the need for high melting points while maintaining Tg
Solution Approach 2:
The vinyl group acts as an intermediary that enables the flame retardant to participate in the polymerization reaction. This intermediary function allows the flame retardant to transition from an external additive to an integrated component of the resin network, achieving both easy dispersibility and thermal stability
3Stability of the object's composition
If reactive flame retardants are used to achieve uniform distribution, then dispersibility is improved, but compatibility with varnish components and electrical properties deteriorate
Solution Approach 1:
The invention changes the reactivity parameter of the flame retardant by selecting a vinyl group that undergoes radical polymerization rather than cationic or anionic polymerization. This parameter change ensures compatibility with the varnish components and curing system while achieving uniform distribution through chemical bonding in the crosslinked network
Solution Approach 2:
The invention applies local quality by positioning the flame retardant molecules at specific locations within the crosslinked network through radical polymerization. This localized integration ensures uniform distribution while maintaining the electrical properties of the resin system, as the flame retardant is distributed throughout the network rather than concentrated in specific regions
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 composition achieves a low dissipation factor of 0.0022 and dielectric constant of 2.72 at 80 GHz, with a glass transition temperature above 216°C and thermal expansion ratio below 2.70%, addressing the limitations of conventional resins.
Implementation Method 1
4-vinylbenzyl diphenylphosphine oxide having the formula (I): and wherein the composition is in the absence of a maleimide resin
Implementation Method 2
processing the prepreg at elevated temperature to promote partial cure to a B-stage
Data Source
AI summary
There is provided herein a flame retarded, halogen free resin composition comprising(a) a free radically polymerizable monomer or oligomer; and,(b) 4-vinylbenzyl diphenylphosphine oxide having the formula (I):and wherein the composition is in the absence of a maleimide resin. There is also provided an article which may be made from the composition, which article can be a prepreg, a resin film, a laminate, or a printed circuit board. The said article has low dielectric loss at a very high frequency.