Polybutadiene PCB Resin Composition for Lower Curing Temperatures

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Solution Overview

Problem

Existing polybutadiene-based printed circuit board (PCB) materials face issues with weak substrate strength, poor electric properties, high curing temperatures, stickiness, and hygroscopicity, which affect heat resistance, mechanical strength, and peeling strength with copper foils.

Innovation Solution

A polybutadiene-based PCB composition with high vinyl content polybutadiene resin, cycloolefin compounds, and metallic coagents, combined with particulate fillers and brominated flame retardants, is developed to enhance crosslinking density, reduce stickiness, and improve peeling strength, allowing for lower curing temperatures and better thermal expansion coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high curing temperature (above 250°C) is used to cure polybutadiene or polyisoprene resin, then crosslinking density and heat resistance are improved, but the bromine flame retardant decomposes and physical properties deteriorate

Engineering Contradiction:
Improvecuring temperatureVSAvoidflame retardant stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the curing temperature parameter from above 250°C to below 200°C, and modifies the resin composition by incorporating epoxy resin with polybutadiene or polyisoprene resin. This parameter change allows curing at lower temperatures that do not decompose the bromine flame retardant, while still achieving adequate crosslinking density and heat resistance through the combined resin system and peroxide initiator.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If polybutadiene or polyisoprene resin is used to make prepreg, then the resin cures at high temperature, but the prepreg becomes too sticky to conduct automatic continuous pressing

Engineering Contradiction:
Improvecuring temperatureVSAvoidprepreg stickiness
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent creates a composite material system by combining polybutadiene or polyisoprene resin with epoxy resin in specific proportions. This composite resin system maintains the beneficial properties of polybutadiene/polyisoprene (heat resistance, crosslinking) while the epoxy component reduces stickiness during handling, enabling automatic continuous pressing operations.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If high proportion of particulate filler (over 50 wt%) is used in circuit board composition, then non-stickiness and ease of handling are improved, but impregnation difficulty and drill head wearing increase

Engineering Contradiction:
Improvehandling easeVSAvoidimpregnation difficulty
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent optimizes the filler content parameter to a balanced range of 30-50 wt% rather than exceeding 50 wt%. This parameter adjustment maintains adequate non-stickiness and handling ease while reducing impregnation difficulty and drill head wearing. The balanced filler proportion allows proper resin flow and copper foil impregnation during the lamination process.

Inventive Principle:
Principle #35Parameter changes

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 superior heat resistance, improved mechanical strength, reduced hygroscopicity, and enhanced peeling strength with copper foils, while enabling lower curing temperatures and more efficient processing, resulting in better electrical properties and flame retardancy.

Implementation Method 1

a peroxide initiator

Methodology Applied
Scientific EffectFree radical polymerization: Photopolymerisation

Implementation Method 2

the adhesion between resin and copper and woven cloth is enhanced on addition of silane

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP1930371B1Polybutadiene thermosetting resin printed circuit board composition and the process thereof
Publication Date: 2009.09.02 NANYA PLASTICS CORP

AI summary

The present invention is about a composition for high performance printed circuit board. Said composition includes 20-35 wt% of high molecular polymer of high molecular weight of polybutadiene with high vinyl groups, low molecular weight of polybutadiene and cyclic olefin polymer with two or above vinyl groups, and/or thermosetting polymer resin which was polymerized from acrylic acid, acrylonitrile and butadiene; 10-30 wt% woven glass fiber reinforced cloth; 25-50 wt% inorganic particulate filler; 1-10 wt% metallic coagents; 10-30 wt% brominated flame retardant. Using solvents to dilute the composition to the suitable viscosity, then after the resin sheet (prepreg) had been made by impregnation, the electric circuit board composition with excellent properties can be obtained by laminating at 170-220°C with 20-50 kg/cm2.