News Details
Waterborne epoxy coatings used crosslinking agent
2017-8-22 11:41:23
Waterborne epoxy coatings used crosslinking agent
The infrared spectrum proves that even in the case of overdose of water-based epoxy, there are epoxy groups in the crosslinking products of water-based epoxy.
Through the coating hardness, resistance to salt spray and electrochemical impedance spectroscopy analysis of waterborne epoxy coatings in waterborne epoxy crosslinking agent without too much the performance of the coating increases with the amount of crosslinking agent and improve, in waterborne epoxy crosslinking agent under the condition of excessive the performance of the coating decreases with the increase of crosslinking agent, when m (epoxy emulsion) : m (cross-linking agent) = 4.5:1 when the performance of the optimal coating.
Comparison of different dosage of crosslinking agent | Z | 0.01 changing with time curve, it can be seen at the beginning of the soak, sample 1 | Z | 0.01 largest decline, as the crosslinking agent excess of most, due to the strong hydrophilicity of crosslinking agent, promoted the salt water penetration to the inside coating. As the soaking time increased, the anticorrosion pigment began to play its passivation effect, forming a passivation layer in the coating and steel interface, and | Z | 0.01 began to increase. With the further increase of soaking time, the corrosion further expanded, gradually damaging the passivation layer, resulting in the reduction of | Z | 0.01.
In addition, in the initial stage, the | Z | 0.01 value of the sample 4 was lower, namely, when the dosage of crosslinking agent was lower, the average cross-linking density of the coating was lower and the anti-permeability ability was low.
Sample 3 has been at the highest peak of | Z | 0.01 relative to other samples during the whole soaking process, which further illustrates that the corrosion resistance is optimal when m (epoxy emulsion) is equal to 4.5:1.
Soak time 1 d and 5 d, respectively, the Nyquist the graph is a semicircle, with the increase of immersion time, began to appear on Nyquist diagram 2 semicircle of the trend, and the high frequency end radius increased after the first decreases with increasing soaking time. This is because when the immersion time within 5 d, electrochemical corrosion phenomenon has not yet occurred, therefore, Nyquist the graph is a semicircle, that is, a time constant, but the salt water into internal coating, ac impedance is reduced, cause the Nyquist figure high-frequency end radius is smaller.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
The infrared spectrum proves that even in the case of overdose of water-based epoxy, there are epoxy groups in the crosslinking products of water-based epoxy.
Through the coating hardness, resistance to salt spray and electrochemical impedance spectroscopy analysis of waterborne epoxy coatings in waterborne epoxy crosslinking agent without too much the performance of the coating increases with the amount of crosslinking agent and improve, in waterborne epoxy crosslinking agent under the condition of excessive the performance of the coating decreases with the increase of crosslinking agent, when m (epoxy emulsion) : m (cross-linking agent) = 4.5:1 when the performance of the optimal coating.
Comparison of different dosage of crosslinking agent | Z | 0.01 changing with time curve, it can be seen at the beginning of the soak, sample 1 | Z | 0.01 largest decline, as the crosslinking agent excess of most, due to the strong hydrophilicity of crosslinking agent, promoted the salt water penetration to the inside coating. As the soaking time increased, the anticorrosion pigment began to play its passivation effect, forming a passivation layer in the coating and steel interface, and | Z | 0.01 began to increase. With the further increase of soaking time, the corrosion further expanded, gradually damaging the passivation layer, resulting in the reduction of | Z | 0.01.
In addition, in the initial stage, the | Z | 0.01 value of the sample 4 was lower, namely, when the dosage of crosslinking agent was lower, the average cross-linking density of the coating was lower and the anti-permeability ability was low.
Sample 3 has been at the highest peak of | Z | 0.01 relative to other samples during the whole soaking process, which further illustrates that the corrosion resistance is optimal when m (epoxy emulsion) is equal to 4.5:1.
Soak time 1 d and 5 d, respectively, the Nyquist the graph is a semicircle, with the increase of immersion time, began to appear on Nyquist diagram 2 semicircle of the trend, and the high frequency end radius increased after the first decreases with increasing soaking time. This is because when the immersion time within 5 d, electrochemical corrosion phenomenon has not yet occurred, therefore, Nyquist the graph is a semicircle, that is, a time constant, but the salt water into internal coating, ac impedance is reduced, cause the Nyquist figure high-frequency end radius is smaller.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
With the increase of immersion time, two time constants have started to occur, which is that microscopic electrochemical corrosion has begun to occur. Due to the passivation of anticorrosive pigment, the dense passivation layer formed, resulting in increased communication impedance, and the high frequency radius of Nyquist diagram began to increase. With the further increase of soaking time, the passivation layer was destroyed and the diameter of the curve began to decrease.
With the development of modern science and technology and modern industry, environmental pollution poses a great threat to the earth and human beings on which people live.
Traditional coatings contain a large amount of solvents that are discharged into the atmosphere during manufacturing and construction. Low carbon environmental protection is the outlet of waterborne crosslinking agent, and the best use of environmental protection paint crosslinking agent to replace the solvent based paint crosslinking agent, so as to make the coating crosslinking agent comprehensive environmental protection and waterborne. It is a revolution for water paint to replace paint, which is inevitable for human survival and scientific and technological development.
Development of heavy-duty powder coatings with epoxy resins and crosslinking agent technical indexes and performance close to the level of similar foreign products, can meet the requirements of steel pipe heavy-duty epoxy powder coating.
Use two step method, the mixture of phenolic epoxy resin, polymer end hydroxyl compounds with anionic catalytic crosslinking agent of epoxy crosslinking agent system, can meet the processing requirements of heavy-duty powder coatings and coating mechanical, electrical and chemical resistance and other performance requirements.
The factors influencing the synthesis of epoxy resin are: linear phenolic resin composition, raw material ratio, reaction temperature and time; The factors that affect the performance of crosslinking agent are: the composition and molecular weight of macromolecular hydroxyl group and the dosage of the catalytic crosslinking agent.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
With the increase of immersion time, two time constants have started to occur, which is that microscopic electrochemical corrosion has begun to occur. Due to the passivation of anticorrosive pigment, the dense passivation layer formed, resulting in increased communication impedance, and the high frequency radius of Nyquist diagram began to increase. With the further increase of soaking time, the passivation layer was destroyed and the diameter of the curve began to decrease.
With the development of modern science and technology and modern industry, environmental pollution poses a great threat to the earth and human beings on which people live.
Traditional coatings contain a large amount of solvents that are discharged into the atmosphere during manufacturing and construction. Low carbon environmental protection is the outlet of waterborne crosslinking agent, and the best use of environmental protection paint crosslinking agent to replace the solvent based paint crosslinking agent, so as to make the coating crosslinking agent comprehensive environmental protection and waterborne. It is a revolution for water paint to replace paint, which is inevitable for human survival and scientific and technological development.
Development of heavy-duty powder coatings with epoxy resins and crosslinking agent technical indexes and performance close to the level of similar foreign products, can meet the requirements of steel pipe heavy-duty epoxy powder coating.
Use two step method, the mixture of phenolic epoxy resin, polymer end hydroxyl compounds with anionic catalytic crosslinking agent of epoxy crosslinking agent system, can meet the processing requirements of heavy-duty powder coatings and coating mechanical, electrical and chemical resistance and other performance requirements.
The factors influencing the synthesis of epoxy resin are: linear phenolic resin composition, raw material ratio, reaction temperature and time; The factors that affect the performance of crosslinking agent are: the composition and molecular weight of macromolecular hydroxyl group and the dosage of the catalytic crosslinking agent.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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