Sunlight Curable Coating Composition Oxygen Inhibition
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Solution Overview
Problem
Traditional coatings lack superior hardness and flexibility due to oxygen inhibition during curing, and existing technologies require additional film formers or plasticizers to achieve desirable properties.
Innovation Solution
A coating composition comprising high molecular weight polyurethane acrylate or methacrylate, an alcohol solubilizer, and a visible light photoinitiator, which forms a hard film upon solvent evaporation, reducing oxygen inhibition and enhancing curing under ambient sunlight, thereby improving hardness and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional UV light curing equipment is used, then curing speed is improved, but oxygen inhibition prevents achieving superior hardness
Solution Approach 1:
The patent converts the harmful effect of oxygen inhibition into a beneficial extended curing process. Instead of trying to eliminate oxygen inhibition, the formulation allows the coating to initially cure quickly under UV light despite oxygen presence, then continue crosslinking overnight at ambient conditions to achieve superior hardness that actually exceeds UV-cured coatings.
Solution Approach 2:
The coating performs preliminary curing action during UV exposure to establish initial film formation and basic properties, then continues crosslinking in the absence of UV light to achieve final superior hardness. This two-stage approach allows the coating to benefit from both rapid initial curing and extended ambient crosslinking.
2Strength
If high molecular weight polyurethane acrylate is used, then film hardness is improved, but formulation complexity increases
Solution Approach 1:
The patent achieves superior hardness by changing the molecular weight parameter of the polyurethane acrylate to high molecular weight (10,000-100,000 Daltons), which inherently provides better film-forming properties and hardness. The specific molecular weight range was selected to optimize the balance between hardness, flexibility, and ease of formulation.
Solution Approach 2:
The formulation creates a composite system combining high molecular weight polyurethane acrylate with specific photoinitiators (visible light and UV), alcohols, and non-alcohol solvents. This composite approach allows the high molecular weight polymer to provide film hardness while the other components ensure proper curing, solubility, and application properties.
3Stability of the object's composition
If additional film formers or plasticizers are added, then coating flexibility is improved, but coating simplicity is reduced
Solution Approach 1:
The high molecular weight polyurethane acrylate performs multiple functions simultaneously: it provides film formation, delivers superior hardness, and ensures adequate flexibility. This multi-functional polymer eliminates the need for separate plasticizers or additional film formers, maintaining coating simplicity while achieving desired performance.
Solution Approach 2:
The patent changes the molecular weight parameter of the polyurethane acrylate to high molecular weight, which inherently provides both film-forming capability and flexibility. This parameter change allows the single polymer to replace multiple additives, maintaining formulation simplicity while achieving the desired balance of hardness and flexibility.
4Object-affected harmful factors
If sunlight exposure is used for curing, then oxygen inhibition is reduced, but curing time is extended
Solution Approach 1:
The coating performs preliminary curing action during UV exposure to establish initial film formation and basic properties, then continues crosslinking in the absence of UV light to achieve final superior hardness. This two-stage approach allows the coating to benefit from both rapid initial curing and extended ambient crosslinking.
Solution Approach 2:
The crosslinking reaction continues continuously from UV exposure through ambient sunlight exposure. The coating does not stop curing when UV light is removed; instead, the crosslinking process continues uninterrupted under ambient conditions, ultimately achieving superior hardness that exceeds UV-only curing.
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 coating achieves superior hardness and flexibility, with increased pencil hardness and abrasion resistance after sunlight exposure, outperforming UV-cured coatings and eliminating the need for additional film formers or plasticizers.
Implementation Method 1
a photoinitiator in an amount sufficient to polymerize the polyurethane film-forming polymers when exposed to light energy having a wavelength of 395 nm or above
Implementation Method 2
after evaporation of the solvents, namely a tack free surface, good hardness, good flexibility, and abrasion resistance
Data Source
AI summary
A coating composition capable of curing to a high hardness by exposure to sunlight. More particularly, the coating composition comprises a high molecular weight polyurethane (meth)acrylate or methacrylate dissolved in one or more non-alcohol solvent, a visible light photoinitiator, and an alcohol solubilizer.