News Details
Crosslinking agent for thermosetting coatings
2017-6-30 15:58:40
Crosslinking agent for thermosetting coatings
The influence of temperature and other factors on the film process. Need to bake when thermosetting coating film, when temperature increases the viscosity of the coating decreases, the flow leveling as well as improve the adhesion of paint film is good, but if there is excessive viscosity reducing sags can also cause problems. The viscosity of ordinary paint changes slowly with temperature, while the viscosity of high solid paint is much larger than that of ordinary coatings.
So when the wet film into the high temperature oven, viscosity fell sharply, leading to sagging, the sags "oven" is difficult to use the general thixotropic agent (such as gas phase SiO2) overcome: on the one hand, to join the thixotropic agent can increase the viscosity, must add solvent to keep the viscosity, on the other hand, ordinary thixotropic agent lose effectiveness at high temperature.
In order to overcome the oven sag can use "hanging flow control agent", for example, in using a kind of low molecular weight polyester containing urea base structure of semi crystalline compound, it can be melted in the process of curing and can react with crosslinking agent, another way to control the oven sag is reactive microgel.
High solids coatings before entering the oven also easy generation sag, the reason may be that when spraying paint drops of spray gun mouth to the surface only less solvent loss, and the most common coating solvents in the process of escape, so the coated surfaces of two kinds of coating solids is nearly the same, but the high solids low viscosity.
There are three reasons why high solid coatings are less volatile during spraying.
Due to the high solid content, the fog is not good, the fog droplets are larger, the surface area is smaller;
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine packingļ¼ net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Due to high polarity, the solvent and low polymer interact strongly and the solvent is not easy to escape.
The further volatilization of the solvent is controlled by the diffusion velocity.
As car flashing paint coatings, high solid coatings in the sheet metal directional sex than ordinary paint coating is difficult, its reason is not clear, may be because of less solvent, solvent to escape the slow, difficult to form a good internal flow of solvent, is not easy to make sheet metal under the solvent flow orientation.
In addition, due to a high solids coatings surface tension is higher than ordinary coatings, so when the coating on the surface tension is low or by contamination of the surface, very easy generation shrunk (crawling), such as for plastic coated on the surface, shrunk serious situation than normal coatings. The surface tension of the droplet of various viscous or oven drops is lower than the surface tension of the high solid coating, so it is also prone to shrinkage.
Two-component polyurethane coating with low film-forming temperature, good adhesion, abrasion resistance, hardness and chemical resistance, good weatherability and superior performance, as a wide range of industrial protective paint, wood furniture and car. The water-based two-component polyurethane coating combines the high performance of the two-component solvent and the low VOC content of the water-based coating, and becomes the research hotspot of the coating industry. Waterborne two-component polyurethane coatings by containing - OH the base of multivariate alcohol and water with - NCO based low viscosity of isocyanate curing agent, its coating performance is mainly determined by the composition and structure of hydroxyl resin.
Single component waterborne polyurethane coating is based on waterborne polyurethane resin and is a kind of coating with water as dispersing medium. Through crosslinking modification of waterborne polyurethane coating has good storage stability, film mechanical properties, water resistance, solvent resistance and aging resistance, and close to the performance of the conventional solvent-based polyurethane coating, is an important development direction of waterborne polyurethane coatings.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
The influence of temperature and other factors on the film process. Need to bake when thermosetting coating film, when temperature increases the viscosity of the coating decreases, the flow leveling as well as improve the adhesion of paint film is good, but if there is excessive viscosity reducing sags can also cause problems. The viscosity of ordinary paint changes slowly with temperature, while the viscosity of high solid paint is much larger than that of ordinary coatings.
So when the wet film into the high temperature oven, viscosity fell sharply, leading to sagging, the sags "oven" is difficult to use the general thixotropic agent (such as gas phase SiO2) overcome: on the one hand, to join the thixotropic agent can increase the viscosity, must add solvent to keep the viscosity, on the other hand, ordinary thixotropic agent lose effectiveness at high temperature.
In order to overcome the oven sag can use "hanging flow control agent", for example, in using a kind of low molecular weight polyester containing urea base structure of semi crystalline compound, it can be melted in the process of curing and can react with crosslinking agent, another way to control the oven sag is reactive microgel.
High solids coatings before entering the oven also easy generation sag, the reason may be that when spraying paint drops of spray gun mouth to the surface only less solvent loss, and the most common coating solvents in the process of escape, so the coated surfaces of two kinds of coating solids is nearly the same, but the high solids low viscosity.
There are three reasons why high solid coatings are less volatile during spraying.
Due to the high solid content, the fog is not good, the fog droplets are larger, the surface area is smaller;
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine packingļ¼ net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Due to high polarity, the solvent and low polymer interact strongly and the solvent is not easy to escape.
The further volatilization of the solvent is controlled by the diffusion velocity.
As car flashing paint coatings, high solid coatings in the sheet metal directional sex than ordinary paint coating is difficult, its reason is not clear, may be because of less solvent, solvent to escape the slow, difficult to form a good internal flow of solvent, is not easy to make sheet metal under the solvent flow orientation.
In addition, due to a high solids coatings surface tension is higher than ordinary coatings, so when the coating on the surface tension is low or by contamination of the surface, very easy generation shrunk (crawling), such as for plastic coated on the surface, shrunk serious situation than normal coatings. The surface tension of the droplet of various viscous or oven drops is lower than the surface tension of the high solid coating, so it is also prone to shrinkage.
Two-component polyurethane coating with low film-forming temperature, good adhesion, abrasion resistance, hardness and chemical resistance, good weatherability and superior performance, as a wide range of industrial protective paint, wood furniture and car. The water-based two-component polyurethane coating combines the high performance of the two-component solvent and the low VOC content of the water-based coating, and becomes the research hotspot of the coating industry. Waterborne two-component polyurethane coatings by containing - OH the base of multivariate alcohol and water with - NCO based low viscosity of isocyanate curing agent, its coating performance is mainly determined by the composition and structure of hydroxyl resin.
Single component waterborne polyurethane coating is based on waterborne polyurethane resin and is a kind of coating with water as dispersing medium. Through crosslinking modification of waterborne polyurethane coating has good storage stability, film mechanical properties, water resistance, solvent resistance and aging resistance, and close to the performance of the conventional solvent-based polyurethane coating, is an important development direction of waterborne polyurethane coatings.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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