Resin Composition for Rigid-Flex Boards
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Solution Overview
Problem
Conventional resin compositions for rigid-flex boards face challenges in achieving high bonding strength, thermal resistance, and reliability due to issues with low flow prepregs, leading to problems such as solder pad fall-off during high-temperature soldering and increased dust weight loss.
Innovation Solution
A resin composition comprising 100 parts by weight of epoxy resin, 2 to 50 parts by weight of carboxyl-containing butadiene acrylonitrile resin, 1 to 40 parts by weight of phosphazene, and 1 to 8 parts by weight of acrylic triblock copolymer, which enhances bonding strength, thermal resistance, and peel strength, while reducing dust weight loss and stickiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If low flow prepregs are used to connect flexible boards and rigid boards, then bonding strength is improved, but solder pad fall-off occurs during high-temperature soldering
Solution Approach 1:
The patent uses a composite resin composition containing epoxy resin, carboxyl-containing butadiene acrylonitrile resin, phosphazene, and acrylic triblock copolymer. This multi-component composite system combines the high bonding strength of epoxy with the thermal stability of phosphazene and the flexibility of butadiene acrylonitrile resin, achieving both strong bonding and solder pad retention at high temperatures.
Solution Approach 2:
The patent modifies the chemical composition parameters of the prepreg by incorporating specific ratios of carboxyl-containing butadiene acrylonitrile resin (2-50 parts), phosphazene (1-40 parts), and acrylic triblock copolymer (1-8 parts) per 100 parts of epoxy resin. These parameter changes optimize the balance between bonding strength and thermal resistance to prevent solder pad fall-off.
2Ease of manufacture
If conventional resin compositions are used, then low flow property is achieved, but dust weight loss increases during cutting
Solution Approach 1:
The addition of phosphazene and acrylic triblock copolymer to the epoxy resin system creates a composite material with improved cohesive strength. This composite structure reduces dust generation during cutting while maintaining the low flow property necessary for proper prepreg performance in rigid-flex board fabrication.
3Ease of manufacture
If conventional resin compositions are used, then low cost is maintained, but thermal resistance and peel strength are insufficient
Solution Approach 1:
The patent incorporates phosphazene (1-40 parts per 100 parts epoxy resin), which provides exceptional thermal stability and flame retardancy. This parameter change in the resin composition significantly improves thermal resistance while maintaining cost-effectiveness through optimized ingredient ratios.
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 resin composition achieves a yield rate of greater than 80% in solder pad fall-off tests at high temperatures, low dust weight loss, high peel strength, and improved thermal resistance, ensuring the reliability and performance of rigid-flex boards.
Implementation Method 1
the resin composition comprises: (A) 100 parts by weight of epoxy resin; (B) 2 to 50 parts by weight of carboxyl-containing butadiene acrylonitrile resin
Implementation Method 2
the bonding strength between low flow prepregs and flexible boards is important to the product reliability, the peel strength between the prepreg and the medium contacted therewith after lamination is measured to evaluate the bonding strength
Implementation Method 3
1 to 40 parts by weight of phosphazene; high thermal resistance
Implementation Method 4
1 to 8 parts by weight of acrylic triblock copolymer; low stickiness
Data Source
AI summary
A resin composition comprises 100 parts by weight of epoxy resin; 2 to 50 parts by weight of carboxyl-containing butadiene acrylonitrile resin; 1 to 40 parts by weight of phosphazene; and 1 to 8 parts by weight of acrylic triblock copolymer. The resin composition may be made into various articles, such as prepregs, laminates, printed circuit boards or rigid-flex boards, and meets one, more or all of the following properties: high yield rate in solder pad fall-off test at high temperature, low dust weight loss, low stickiness, high thermal resistance, high peel strength to copper foil, and high bonding strength to polyimide layer.