Supercritical CO2 Coating Device Preventing Polymer Blockage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current carbon dioxide coating technologies face challenges in achieving practical industrial application due to issues such as imbalance in paint/CO2 ratios, increased pump discharge pressure, blockage problems, and instability in operation, particularly with one-liquid curing type paints, which hinder the development of efficient and environmentally friendly coating methods.
Innovation Solution
A novel coating method and device utilizing a high-pressure micro mixer and specific operating procedures to stabilize the carbon dioxide coating process, incorporating a high-pressure micro mixer for efficient mixing and a T-shaped or double tube style micro mixer to prevent polymer deposition, along with a spray gun design that allows for controlled spraying and efficient use of carbon dioxide, thereby ensuring stable operation and reduced VOC emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If carbon dioxide is used as a viscosity lowering agent in spray coating, then VOC emissions are reduced, but operational stability and coating quality deteriorate due to blockage and imbalance issues
Solution Approach 1:
The patent applies parameter changes by precisely controlling temperature and pressure parameters in the supercritical CO2 coating system. By maintaining CO2 in a supercritical state through controlled parameters (temperature above critical point of 31.1°C and pressure above critical point of 73.8 atm), the system achieves stable operation without blockage while reducing VOC emissions. The parameters of paint composition, CO2 flow rate, and mixing ratio are optimized to prevent polymer deposition.
Solution Approach 2:
The patent uses supercritical CO2 as an intermediary substance between the paint and the coating surface. Instead of directly spraying organic solvents, the system dissolves paint in supercritical CO2, which then acts as a carrier medium. This intermediary approach allows the paint to be delivered without harmful VOC emissions while the CO2 can be precisely controlled to prevent blockage issues.
2Object-affected harmful factors
If carbon dioxide is used as a viscosity lowering agent, then environmental burden is reduced, but manufacturing precision deteriorates due to blockage problems
Solution Approach 1:
The patent maintains coating quality by precisely controlling parameters including temperature (maintaining supercritical state), pressure, CO2 flow rate, and paint composition. These parameter controls prevent polymer deposition and ensure uniform coating application, achieving manufacturing precision equivalent to or better than conventional methods while reducing environmental burden.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and adjust operating parameters in real-time. By monitoring the coating process and detecting any signs of blockage or quality degradation, the system can adjust CO2 flow rate, pressure, or temperature to maintain optimal conditions, ensuring consistent coating quality while maintaining environmental benefits.
3Manufacturing precision
If conventional spray coating with organic solvents is used, then coating quality is maintained, but VOC generation increases significantly
Solution Approach 1:
The patent replaces organic solvents with supercritical CO2 by changing the physical state and composition parameters of the coating medium. This substitution maintains coating finish quality through precise control of CO2 parameters (temperature, pressure, flow rate) while eliminating harmful VOC generation associated with conventional organic solvent-based systems.
Solution Approach 2:
The patent creates an inert coating environment by using supercritical CO2 instead of flammable organic solvents. CO2 provides a non-reactive, non-flammable atmosphere that safely delivers the paint coating while eliminating VOC emissions. The inert nature of CO2 prevents harmful emissions while maintaining the functional properties needed for quality coating application.
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 method and device achieve a significant reduction in VOC emissions while maintaining coating finish quality, preventing blockage issues, and enabling long-term stable operation, making the carbon dioxide coating technology more practical and applicable in industrial settings.
Implementation Method 1
a supercritical fluid, and particularly carbon dioxide, is dissolved in a paint (consisting of a polymer and a true solvent that dissolves the polymer and imparts fluidity) and enables coating by lowering viscosity to a level that enables spraying
Implementation Method 2
a paint/carbon dioxide mixture line constituted by a high-pressure micro mixer for mixing pressurized paint supplied from the paint supply line and pressurized carbon dioxide supplied from the carbon dioxide supply line
Implementation Method 3
a spray gun for spraying the mixed paint/carbon dioxide pressurized mixture supplied from the mixer onto an object to be coated at atmospheric pressure
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a low environmental burden type coating method using carbon dioxide and a coating device therefor that carry out carbon dioxide coating in which carbon dioxide is substituted for all or a portion of a diluent solvent (thinner) used in organic solvent-based spray coating, the coating method being configured to prevent deposition of a polymer of a paint component that has entered as a result of backflow by preliminarily adding, to carbon dioxide, a true solvent component of the paint in at least an amount required for saturated solubility (20% to 50% per weight of carbon dioxide ) to lower the dissolving power of carbon dioxide with respect to the true solvent component. According to the present invention, it is possible to provide a coating method and a device therefor capable of considerably reducing VOC generation, and a coating method and a device therefor capable of performing stable carbon dioxide coating of a one-liquid curing type or two-liquid curing type paint.