Curable Composition Adhesion Flexibility Printed Circuit Board
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Solution Overview
Problem
Conventional photocurable compositions for printed circuit boards exhibit poor flexibility and adhesiveness to plastic substrates and conductor circuit metals, making it difficult to maintain solder heat resistance and achieve satisfactory adhesion.
Innovation Solution
A curable composition comprising a block copolymer, a hydroxyl group-containing (meth)acrylate compound, and a photopolymerization initiator, with specific molecular weight and viscosity ranges, is used to form a pattern-cured coating film that demonstrates excellent adhesion and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional photocurable composition is used, then the coating process is simple and fast, but the coating film has poor flexibility and adhesiveness to plastic substrates and conductor circuit metals
Solution Approach 1:
The patent uses a composite resin composition comprising a polyimide resin and a flexible resin (polybutadiene acrylate or polyurethane acrylate). This composite structure combines the heat resistance of polyimide with the flexibility and adhesiveness of the flexible resin, resolving the contradiction between process simplicity and coating film performance.
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating specific flexible resins with defined molecular weights and functional groups into the photocurable composition. This changes the physical and chemical properties of the coating film to achieve both flexibility and adhesion while maintaining the photocurable process advantages.
2Strength
If the coating film has high flexibility, then adhesion to plastic substrate and conductor circuit metal improves, but solder heat resistance may be compromised
Solution Approach 1:
The patent creates a composite resin system where polyimide resin provides solder heat resistance while flexible resin (polybutadiene acrylate or polyurethane acrylate) provides flexibility and adhesion. The synergistic combination allows both properties to coexist without compromising either.
Solution Approach 2:
The patent applies different resin components to fulfill different functional requirements within the same coating film - the polyimide resin component provides heat resistance locally, while the flexible resin component provides flexibility and adhesion locally, achieving overall performance balance.
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 excellent adhesion to both plastic substrates and conductor circuit metals while maintaining solder heat resistance, suitable for use as an inkjet composition, and exhibits superior properties as a cured coating film.
Implementation Method 1
a photocurable composition that forms a flexible coating film is coated by screen printing and then cured
Data Source
AI summary
Provided are: a curable composition that has excellent flexibility and shows excellent adhesion to both a plastic substrate and a conductor layer; a coating film of the curable composition; and a printed circuit board comprising a pattern-cured coating film obtained from the coating film. The present invention relates to: a curable composition for a printed circuit board, which is characterized by comprising (A) a block copolymer, (B) a hydroxyl group-containing (meth)acrylate compound and (C) a photopolymerization initiator; a coating film obtained by photo-curing the curable composition; and a printed circuit board comprising a resist pattern formed from the coating film.