Aqueous Urethane Coating Composition for Low-Temperature Durable Films
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Solution Overview
Problem
Existing aqueous coating compositions used in low-temperature curing processes for automobile coatings lack sufficient abrasion resistance, chipping resistance, and glass adhesion properties, while also having storage stability issues.
Innovation Solution
An aqueous coating composition comprising a urethane resin particle aqueous dispersion obtained from a secondary amino group- and alkoxysilyl group-containing compound, and an isocyanate group-containing urethane prepolymer, with a curing agent content between 5 to 50% by mass, enhances the coating's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-temperature curing is used to reduce energy consumption, then energy efficiency is improved, but coating film performance (abrasion resistance, chipping resistance, glass adhesion) deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material by incorporating silane-modified polyurethane resin and specific curing agents in optimized ratios. This allows the coating to achieve high-performance crosslinking at lower temperatures without sacrificing abrasion resistance, chipping resistance, or glass adhesion, thus resolving the contradiction between energy efficiency and coating performance
Solution Approach 2:
The patent uses a composite coating system combining silane-modified polyurethane resin with specific curing agents (polybasic amine or hydroxyl-terminated polyisocyanate). This composite approach enables low-temperature curing while maintaining excellent coating film properties, as the synergistic interaction between components creates strong crosslinked networks that provide both energy efficiency and reliability
2Reliability
If high reactivity coating composition is used to achieve low-temperature curing, then curing performance is improved, but storage stability deteriorates
Solution Approach 1:
The patent carefully controls the reactivity parameters by selecting specific curing agents with appropriate functional group contents and molecular weights. The polybasic amine curing agent is used in controlled amounts (0.1-10.0 parts by mass per 100 parts of resin), and hydroxyl-terminated polyisocyanate is used in specific ratios (1:0.95 to 1:0.05). This parameter optimization allows the coating to remain stable during storage while achieving excellent curing performance when applied
Solution Approach 2:
The patent introduces silane-modified polyurethane resin as an intermediary component that bridges the contradiction between reactivity and stability. The silane groups provide controlled reactivity for crosslinking during curing, while the polyurethane backbone maintains storage stability. This intermediary substance enables the coating system to achieve both low-temperature curing performance and long-term stability
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 improved storage stability and enhances abrasion resistance, chipping resistance, and glass adhesion properties even when cured at relatively low temperatures.
Implementation Method 1
an aqueous coating composition comprising: a urethane resin (A) particle aqueous dispersion which is obtained from a component containing a secondary amino group- and alkoxysilyl group-containing compound (a1), and an isocyanate group-containing urethane prepolymer (a2); and a curing agent (B)
Implementation Method 2
a component containing a secondary amino group- and alkoxysilyl group-containing compound (a1)... the secondary amino group- and alkoxysilyl group-containing compound (a1) is obtained from a component containing a primary amino group- and alkoxysilyl group-containing compound (a11) and a polymerizable unsaturated group-containing compound (a12)
Data Source
AI summary
The purpose of the present invention is to provide an aqueous coating material composition which exhibits excellent storage stability and can form a coating film having excellent abrasion resistance, chipping resistance and adhesion to glass even if cured at a relatively low temperature. This aqueous coating material composition contains: an aqueous dispersion of particles of a urethane resin (A) obtained from a compound (a1) having a secondary amino group and an alkoxysilyl group and an isocyanate group-containing urethane prepolymer (a2); and a curing agent (B). The aqueous coating material composition is characterized in that: the compound (a1) having a secondary amino group and an alkoxysilyl group is obtained from constituent components including a compound (a11) containing a primary amino group and an alkoxysilyl group and a polymerizable unsaturated group-containing compound (a12); and the content of the curing agent (B) falls within the range 5-50 mass % relative to the total amount of solid resin content in the aqueous coating material composition.