Inkjet Curable Composition for Crack-Resistant Solder Resist Coatings
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Solution Overview
Problem
Conventional curable compositions for inkjet printing primarily composed of monomers result in low molecular weight and viscosity, leading to insufficient heat resistance and issues like cracks and peeling in coating films due to thermal history, especially in applications like solder resist for printed circuit boards.
Innovation Solution
A curable composition for inkjet printing comprising specific blends of (meth)acrylate monomers with cyclic skeletons, bifunctional monomers with alkylene glycol structures, and a photopolymerization initiator, optimized in mass ratios to enhance heat resistance and crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high molecular weight polymers are used to improve heat resistance, then heat resistance is improved, but viscosity increases making the composition unsuitable for inkjet printing
Solution Approach 1:
The patent changes the molecular weight parameter of the polymer from high to low, and compensates for heat resistance by adjusting the chemical composition (using specific monomers with carboxyl, hydroxyl, or amine groups). This allows achieving heat resistance through chemical structure rather than molecular weight, thereby maintaining low viscosity suitable for inkjet printing.
Solution Approach 2:
The patent creates a composite curable composition combining low molecular weight polymer with specific functional monomers (carboxylic acid, hydroxyl, or amine groups). This composite approach achieves heat resistance through the synergistic interaction of components rather than relying on high molecular weight alone, while maintaining low viscosity.
2Force
If low viscosity monomer-based compositions are used for inkjet printing, then viscosity is reduced enabling inkjet application, but heat resistance becomes insufficient causing cracks and peeling after thermal history
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific functional groups (carboxyl, hydroxyl, amine) in controlled amounts. These functional groups enhance intermolecular interactions and crosslinking density, improving heat resistance without significantly increasing viscosity, thus maintaining inkjet printability.
Solution Approach 2:
The patent introduces functional monomers with specific local chemical properties (carboxyl, hydroxyl, or amine groups) into the polymer structure. These localized functional groups provide targeted heat resistance enhancement through hydrogen bonding and crosslinking, while the overall low molecular weight structure maintains low viscosity for inkjet application.
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 forms a coating film with enhanced heat resistance, preventing cracks and maintaining adhesion after repetitive heating, suitable for solder resist applications.
Implementation Method 1
a photopolymerization initiator
Data Source
Figure 1
AI summary
[Problem to be Solved] Provided is a curable composition for inkjet printing, a coating film obtained from which has higher heat resistance than conventional coating films. [Solution] It is a curable composition for inkjet printing, comprising (A) a (meth)acrylate monomer having a cyclic skeleton and having a number of alkylene oxide modifications of one or more and six or less, (B1) a bifunctional (meth) acrylate monomer having no cyclic skeleton and having two or more alkylene glycol structures, (B2) a bifunctional (meth) acrylate monomer having no cyclic skeleton and having a monoalkylene glycol structure, and (C) a photopolymerization initiator. Accordingly, an obtained coating film does not crack, has excellent adhesion to a conductor, and maintains sufficient hardness even after a thermal history that corresponds to a plurality of times of soldering. The above problem to be solved is also solved by a curable composition for inkjet printing, comprising (A') a (meth) acrylate monomer having a cyclic skeleton and having a number of alkylene oxide modifications of one or more and six or less, (B1') a bifunctional (meth)acrylate monomer having no cyclic skeleton and having two or more alkylene glycol structures, (B2') a bifunctional (meth)acrylate monomer having no cyclic skeleton and having a monoalkylene glycol structure, and (C') a photopolymerization initiator. [Selected Drawing] None