UV-Curable Primer Coating for Automotive Refinishing
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Solution Overview
Problem
Current radiation-curable coating compositions for automotive refinish and OEM applications require UV-B radiation, necessitating surface wiping to remove uncured layers and are not easily cured by visible light within short times.
Innovation Solution
A coating composition comprising monomers, multifunctional oligomers, pigments/fillers, photoinitiators, and volatile organic solvents, cured using actinic radiation (primarily UV-A) to achieve a dry-to-the-touch state within 30 seconds to 10 minutes without the need for surface wiping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If UV-B radiation is used for curing coating composition, then curing speed is improved, but surface wiping is required to remove uncured portions
Solution Approach 1:
The patent changes the radiation wavelength parameter from UV-B to visible light range (400-700 nm), which allows the coating to cure without requiring surface wiping. This parameter change in the radiation spectrum enables complete curing at the surface while maintaining fast curing speed.
Solution Approach 2:
The patent uses a composite photoinitiator system comprising multiple photoinitiators with different absorption characteristics. This composite approach ensures that the coating composition can be effectively cured by visible light across the 400-700 nm range, achieving complete surface curing without wiping requirements.
2Reliability
If conventional radiation-curable coating composition is used, then curing is achieved, but UV-B radiation hazards are present
Solution Approach 1:
The patent extracts and eliminates the harmful UV-B radiation component from the curing process by designing a coating composition specifically optimized for visible light curing. This removes the hazardous radiation while maintaining effective curing capability through alternative photoinitiators activated by visible light.
Solution Approach 2:
The patent converts the limitation of visible light (lower energy compared to UV-B) into a benefit by selecting photoinitiators specifically designed to absorb visible light wavelengths. This transforms what could be seen as a disadvantage into an advantage, achieving safe and effective curing without harmful radiation.
3Ease of operation
If thick primer coating is applied for sandability, then sanding capability is improved, but curing time increases
Solution Approach 1:
The patent creates a dynamic curing system where the coating progresses from a sandable state to a fully cured state under visible light. The composition is formulated to allow sanding during the curing process or immediately after application, then completes curing when exposed to visible light, providing flexibility in the finishing process.
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 allows for rapid curing to a non-tacky, sandable state without the need for solvent wiping, suitable for vertical surfaces and enabling quick application in automotive refinishing without the hazards associated with UV-B radiation.
Implementation Method 1
a coating composition, which upon cure forms a coating... IV) a component D comprising in the range of from 0.5 percent to 15 percent of one or more photoinitiators... exposing said layer to actinic radiation; and curing said exposed layer
Data Source
AI summary
The present invention is directed to a UV curable coating composition, which includes one or more monomers, one or more multifunctional oligomers, one or more pigments, one or more photoinitiators, and volatile organic solvent. The coating composition can be used as a primer in repairing and refinishing automobiles. The coating composition provides short drying times and a cured coating that does not need to be wiped. A method of applying the coating composition is also provided.