Dual-Reactive Coating Composition for Automotive Clearcoat Cracking
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Solution Overview
Problem
Reactive silane-based systems for automotive coatings face issues such as post-curing cracking and phase separation, which degrade performance and restrict their use due to drawbacks like decreased durability and chemical resistance.
Innovation Solution
A dual-reactive coating composition comprising crosslinkable silane-functional monomers, unsaturated monomers or polymers, initiators, and catalysts, optimized through a specific feeding strategy to reduce monomer residues and enhance film formation, thereby suppressing cracking and improving durability and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive silane-based systems are used for automotive coatings, then chemical resistance and scratch resistance are improved, but post-curing cracking and phase separation occur leading to decreased durability
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific ratios of silane-functional polymers (20-60 wt%), unsaturated polyester resins (30-60 wt%), and reactive diluents (5-30 wt%). This parameter optimization prevents phase separation and post-curing cracking while maintaining chemical resistance, thus resolving the contradiction between reliability and durability
Solution Approach 2:
The patent creates a composite coating system combining silane-functional polymers with unsaturated polyester resins and reactive diluents. This composite approach leverages the complementary properties of each component: silane provides chemical resistance, polyester ensures durability, and reactive diluents prevent cracking, thereby achieving both high reliability and long-term durability
2Strength
If silane-functional polymers are incorporated into coating systems, then scratch resistance is enhanced, but cracking and phase separation lead to decreased appearance quality
Solution Approach 1:
The patent optimizes the concentration of silane-functional polymers within 20-60 wt% and controls the water content at 5-30 wt%, preventing excessive crosslinking that causes cracking. This parameter control maintains scratch resistance while avoiding appearance degradation from cracking and phase separation
3Ease of manufacture
If conventional polymer processing is used to disperse inorganic nanoparticles, then processing simplicity is maintained, but covalent bonding between organic and inorganic phases is insufficient reducing performance
Solution Approach 1:
The patent uses silane-functional groups as intermediary components that bridge inorganic nanoparticles and the organic polymer matrix. These silane groups form covalent bonds with both the inorganic phase and the organic resin, creating strong interfacial adhesion while maintaining processing simplicity through a single-step formulation approach
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 dual-reactive coating composition achieves balanced performance in durability, chemical resistance, and appearance, eliminating cracking and brittleness, and enabling flexible and hard films without additional additives.
Implementation Method 1
Those reactive resins have hydrolysable alkoxysilanes as end groups or on the side chains that react through a hydrolytic mechanism to form silsesquioxane networks
Implementation Method 2
react through a hydrolytic mechanism to form silsesquoxane networks
Implementation Method 3
by dispersing them in monomers, and then allowing the polymerization to form a continuous polymer phase
Data Source
AI summary
Disclosed herein is a dual-reactive composition including a). from 24% to 90% by weight of crosslinkable silane-functional monomer and/or oligomer and/or polymer; b). from 9% to 75% by weight of one monomer and/or unsaturated oligomer and/or unsaturated polymer; c). from 0.5% to 10% by weight of one initiator; and d). from 0.5% to 10% by weight of one catalyst, all weight percentages are based on the total weight of the coating composition and a film obtained from curing and drying of the coating composition as well as a substrate coated with the dual-reactive coating composition. Additionally disclosed herein is a process for preparing the dual-reactive coating composition and a roll-to-roll coating composition and a 1K clearcoat composition including the dual-reactive coating composition.