Sprayable Coating Mixture with Protected Crosslinkable Groups
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Solution Overview
Problem
Current spray technologies for automobile coatings face issues with viscosity increase and clogging due to reactive components, leading to short pot life and inconsistent curing, which can result in unacceptable appearance and prolonged curing times, and the use of thinners increases VOC emissions.
Innovation Solution
A method involving the production of atomized streams of coating components through a spray gun, where the viscosity of the first component remains constant, and the second component is siphoned with a pressurized carrier to form a coating mixture, allowing for controlled viscosity and delayed catalyst addition during atomization, thereby extending pot life and ensuring consistent appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple reactive components are mixed to form a pot mix prior to spraying, then the coating can form a crosslinked polymer network, but the viscosity increases continuously causing short pot life and sprayability issues
Solution Approach 1:
The coating system is divided into separate components stored in different containers. Component A contains the crosslinkable groups and Component B contains the crosslinking agents and catalysts. These components remain separate during storage and transport, preventing premature reaction and viscosity increase, while enabling crosslinking only when mixed at the point of application.
Solution Approach 2:
The components are prepared and stored in their respective containers in advance, with Component A containing pre-formulated crosslinkable groups and Component B containing pre-formulated crosslinking agents. This preliminary preparation allows the components to be ready for mixing without having reacted beforehand, extending the usable pot life.
2Duration of action of moving object
If protected crosslinkable groups are used to extend pot life, then the coating can be stored longer, but the curing rate becomes highly sensitive to ambient humidity with narrow acceptable ranges
Solution Approach 1:
The invention changes the chemical parameters of the crosslinking system by using specific protected crosslinkable groups (orthocarbonates, spiroorthocarbonates, orthoacetates, orthoformates) that deprotect through hydrolysis. The deprotection rate can be controlled by selecting different protected group types, allowing adjustment of curing speed while maintaining long pot life, thus reducing sensitivity to humidity variations.
3Ease of operation
If thinning solvent is added to extend pot life, then the sprayability is improved, but VOC emissions increase and curing time is prolonged
Solution Approach 1:
The invention changes the physical parameters of the coating components by adjusting the viscosity of Component A and Component B separately before mixing. By controlling the viscosity of each component individually and optimizing their ratio upon mixing, the formulation achieves sprayability without requiring excessive thinning solvents, thus reducing VOC emissions while maintaining ease of application.
4Duration of action of moving object
If chemical modifications or additives are used to retard polymerization in the pot mix, then the pot life is extended, but the curing rate after application may be adversely affected
Solution Approach 1:
The retarding effect is achieved not by chemical modifications of the reactive components themselves, but by physical separation of Component A (crosslinkable groups) and Component B (crosslinking agents with catalysts). This segmentation prevents premature reaction without introducing substances that would interfere with the curing rate after mixing and application.
5Ease of manufacture
If catalyst is mixed with other components immediately prior to spraying, then the coating can be applied, but the viscosity increases quickly limiting the working time
Solution Approach 1:
The catalyst is prepared in advance as part of Component B and stored separately from Component A. This preliminary preparation allows the catalyst to be ready for use without having been in contact with the crosslinkable groups, preventing premature initiation of the crosslinking reaction and maintaining workability during the mixing and application 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
This method maintains a consistent viscosity and appearance of the coating over time, extends pot life, and allows for rapid curing while reducing VOC emissions, enabling efficient application and environmental compliance.
Implementation Method 1
producing a first atomized stream of a first coating component of said coating composition through an orifice of said spray gun with a stream of a pressurized carrier
Implementation Method 2
producing a second atomized stream of a second coating component of said coating composition, wherein the second atomized stream is produced by siphoning the second coating component with a siphoning stream selected from the stream of the pressurized carrier
Implementation Method 3
When these pot mixes are spray applied to a substrate, humidity in the air can be enough to cause the hydrolysis reaction to occur and form a crosslinked network
Data Source
Figure 1
Figure 2A~2D
Figure 3~5
AI summary
The present disclosure relates to a method for producing a sprayable mixture containing protected crosslinkable groups. The sprayable mixture has a substantially consistent viscosity and can produce a crosslinked coating composition having a good appearance useful in the painting industry.