Thermosetting Urethane Resin Composition for Self-Healing Coatings
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Solution Overview
Problem
Thermosetting urethane resin compositions with self-healing and antifouling properties lack sufficient elongation, making them unsuitable for applications requiring both durability and flexibility in coatings.
Innovation Solution
A thermosetting urethane resin composition is developed, comprising a main agent with a urethane prepolymer containing a polyol and polyisocyanate without aromatic rings, along with a chain extender, and a curing agent, which forms a film with enhanced self-healing, antifouling properties, and elongation when the percentage of triol and triisocyanate is between 10 to 35 mass %.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hard coating layer is applied to improve scratch resistance and durability, then the surface becomes more resistant to scratching, but the coating becomes brittle and prone to cracking with prolonged use
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by incorporating thermosetting resin components with specific molecular structures that provide both hardness and flexibility. The coating contains polyisocyanate compounds and polyol compounds that create a crosslinked network structure, achieving optimal balance between scratch resistance and resistance to brittleness.
Solution Approach 2:
The patent creates a composite coating system combining thermosetting resin composition with specific additives and modifiers. The multi-component system includes base resin, crosslinking agents, and functional additives that work together to provide both the hardness needed for scratch resistance and the flexibility needed to prevent cracking.
2Reliability
If a self-healing thermosetting resin composition is used to maintain good scratch resistance, then the resin can recover from scratch-like depressions, but the composition does not elongate much and lacks sufficient workability
Solution Approach 1:
The patent optimizes the molecular weight, functional group content, and chemical structure parameters of the polyol and polyisocyanate components. By carefully selecting polymers with specific glass transition temperatures and molecular weights, the coating achieves both self-healing capability through reversible bond formation and sufficient elongation for better workability and flexibility.
3Reliability
If a hard coating layer is applied to prevent scratching, then durability is improved, but once a scratch is made, the scratch remains and degrades the appearance
Solution Approach 1:
The patent implements self-healing functionality where the coating automatically repairs scratches without external intervention. The thermosetting resin composition contains reversible chemical bonds that break under mechanical stress to allow polymer chain movement, then reform to heal the scratch, maintaining appearance and durability over time.
Solution Approach 2:
The patent utilizes phase transition mechanisms in the polymer network, where the coating transitions between different molecular states during the self-healing process. The reversible bond formation and breaking, along with glass transition effects, enable the material to flow and heal scratches while maintaining its solid-state durability.
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 with excellent self-healing, antifouling properties, and elongation, suitable for decorative films and plastic coatings in automotive, home appliances, and electronic devices, maintaining appearance and durability.
Implementation Method 1
The urethane prepolymer (A) has a hydroxy group at an end and contains a composition containing a polyol (a1), a polyisocyanate (a2) and a chain extender (a3)... The curing agent (ii) contains a triisocyanate
Implementation Method 2
a thermosetting urethane resin composition containing a main agent (i) and a curing agent (ii)... forms a film with enhanced self-healing, antifouling properties, and elongation
Data Source
AI summary
A thermosetting urethane resin composition having excellent self-healing properties, antifouling properties, and elongation, a film including a curable coating of the thermosetting urethane resin composition, and a product including the film are provided. The thermosetting urethane resin composition contains a main agent containing a urethane prepolymer and an organic solvent and a curing agent. The urethane prepolymer contains a composition containing a polyol, a polyisocyanate, and a chain extender and has a hydroxy group at an end. The polyol contains a polyol having no aromatic ring. The polyol having no aromatic ring contains liquid and solid polycarbonate polyols. The polyisocyanate contains a polyisocyanate having no aromatic ring. The chain extender contains a low molecular weight triol. The curing agent contains triisocyanate. The percentage of the total amount of the low molecular weight triol and the triisocyanate is 10 mass % or higher and 35 mass % or lower.