Hydroxy Acrylic Curable Composition for Long Pot Life and Fast Cure
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Solution Overview
Problem
Existing curable compositions using resin and polyisocyanate compounds face challenges in balancing usable time with excellent curability and solvent resistance, particularly in applications requiring better coating film properties.
Innovation Solution
A curable composition containing an acrylic polymer with hydroxy groups, a polyisocyanate compound, and a curing catalyst derived from a bismuth compound and an amidine compound, with specific molar ratios and content percentages, to achieve long usable time and excellent curability and solvent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organotin compounds are used as catalysts to promote the reaction between hydroxy groups and isocyanate groups, then curability is improved, but usable time is reduced and harmful effects on human body occur
Solution Approach 1:
The patent replaces persistent organotin compounds with a catalyst system based on bismuth compound and amidine compound that achieves effective catalysis without the harmful environmental and health effects of traditional organotin catalysts
Solution Approach 2:
The patent introduces a specific catalyst system comprising bismuth compound (c1) and amidine compound (c2) as an intermediary substance that mediates the reaction between hydroxy groups and isocyanate groups, achieving effective curability without the harmful effects of organotin compounds
2Duration of action of moving object
If quaternary ammonium carboxylate is used as curing accelerator, then usable time is improved, but coating film properties deteriorate
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using bismuth compound and amidine compound with specific molecular structures and ratios (molar ratio c1/c2 of 0.025 to 0.5), which optimizes both usable time and coating film properties simultaneously
Solution Approach 2:
The patent employs a composite catalyst system combining bismuth compound (c1) and amidine compound (c2) in specific proportions, where the synergistic effect of the composite catalyst system achieves both extended usable time and excellent coating film properties that neither component could achieve alone
3Ease of operation
If longer usable time is achieved, then ease of operation is improved, but curability and solvent resistance deteriorate
Solution Approach 1:
The patent optimizes the catalyst composition parameters by controlling the content of curing catalyst (0.05 to 0.8% by mass relative to copolymer A) and the molar ratio of bismuth compound to amidine compound (0.025 to 0.5), achieving the optimal balance between usable time, curability, and solvent resistance
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 provides a cured product with improved usable time, curability, and solvent resistance, suitable for various coating applications including automotive interiors, automobile repairs, plastics, and industrial machines.
Implementation Method 1
a curing catalyst (C), in which the curing catalyst (C) is derived from a bismuth compound (c1) and an amidine compound (c2)
Data Source
AI summary
Provided is a curable composition containing an acrylic polymer (A) having a hydroxy group, a polyisocyanate compound (B), and a curing catalyst (C), in which the curing catalyst (C) is derived from a bismuth compound (c1) and an amidine compound (c2), the content of the curing catalyst (C) is 0.05 to 0.8% by mass relative to the copolymer (A), and the molar ratio (c1/c2) of the bismuth compound (c1) to the amidine compound (c2) is 0.025 to 0.5. The curable composition has a long usable time and excellent curability and can form a cured product with excellent solvent resistance and hot water resistance. Thus, the curable composition can be suitably used for various coating materials for automotive interiors and exteriors, automobile repairs, plastics, films, industrial machines, building materials, and wood floor, and in-mold coating applications in which molding of a material such as plastic and coating are performed simultaneously in the same mold.