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Powder coating low temperature crosslinking agent
2017-8-17 12:20:29
Powder coating low temperature crosslinking agent
Although the powder coating has the advantages of four "E" (economic-economy, Environmental protection, efficient-efficient, Excellent performance - performance excellence), some of its weaknesses are also obvious. Such as crosslinking is quite harsh conditions, crosslinking temperature is between 180 ~ 200 ℃.
Reducing the crosslinking temperature can reduce energy consumption, which is the need of environmental protection, energy conservation and emission reduction. In addition to high energy consumption, the high temperature of crosslinking has limited the coating of some non-heat-resistant materials such as plastic and wood, which has greatly affected the expansion of powder coating applications.
In terms of further improving efficiency, low temperature crosslinking agent with powder coating is used to reduce the time of crosslinking and increase production efficiency under the condition of keeping the temperature unchanged. Therefore, the research on the low temperature crosslinking agent of powder coating has become one of the development directions of powder coatings industry.
For a long time, the powder coating and related fields such as raw materials and equipment have made a lot of progress in powder coating low temperature crosslinking agent. Now pure epoxy system sand grain effect products can do 130 ℃ / crosslinking 15 minutes. Plane highlights epoxy system can do 140 ℃ / crosslinking 15 minutes.
However, the resistance of epoxy to yellowing and weathering can not be used for outdoor use. Compared with epoxy system better resistance to yellowing of the polyester/epoxy hybrid system sand grain products can do 135 ℃ / 15 minutes, the plane specular products can do 150 ℃ / 15 minutes crosslinking (flow leveling is a bit poor).
Pure polyester system sand grain products can do 140 ℃ / 15 minutes crosslinking, plane highlights crosslinking can be 160 ℃ / 15 minutes. But it is still difficult to get a pure polyester system flat. It is very difficult to realize the ultra-low temperature crosslinking of powder coatings.
First of all, powder coating crosslinked system is a kind of latent crosslinking system at low temperature, low temperature high reactivity, if the system is bound to affect the powder powder extrusion and storage stability, on the other hand powder coating resin and the crosslinking agent are adopted by the solid high softening point, melt viscosity at low temperature is higher, in the crosslinking of low temperature and coating flow flat hard, affect the surface effect.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Although the powder coating has the advantages of four "E" (economic-economy, Environmental protection, efficient-efficient, Excellent performance - performance excellence), some of its weaknesses are also obvious. Such as crosslinking is quite harsh conditions, crosslinking temperature is between 180 ~ 200 ℃.
Reducing the crosslinking temperature can reduce energy consumption, which is the need of environmental protection, energy conservation and emission reduction. In addition to high energy consumption, the high temperature of crosslinking has limited the coating of some non-heat-resistant materials such as plastic and wood, which has greatly affected the expansion of powder coating applications.
In terms of further improving efficiency, low temperature crosslinking agent with powder coating is used to reduce the time of crosslinking and increase production efficiency under the condition of keeping the temperature unchanged. Therefore, the research on the low temperature crosslinking agent of powder coating has become one of the development directions of powder coatings industry.
For a long time, the powder coating and related fields such as raw materials and equipment have made a lot of progress in powder coating low temperature crosslinking agent. Now pure epoxy system sand grain effect products can do 130 ℃ / crosslinking 15 minutes. Plane highlights epoxy system can do 140 ℃ / crosslinking 15 minutes.
However, the resistance of epoxy to yellowing and weathering can not be used for outdoor use. Compared with epoxy system better resistance to yellowing of the polyester/epoxy hybrid system sand grain products can do 135 ℃ / 15 minutes, the plane specular products can do 150 ℃ / 15 minutes crosslinking (flow leveling is a bit poor).
Pure polyester system sand grain products can do 140 ℃ / 15 minutes crosslinking, plane highlights crosslinking can be 160 ℃ / 15 minutes. But it is still difficult to get a pure polyester system flat. It is very difficult to realize the ultra-low temperature crosslinking of powder coatings.
First of all, powder coating crosslinked system is a kind of latent crosslinking system at low temperature, low temperature high reactivity, if the system is bound to affect the powder powder extrusion and storage stability, on the other hand powder coating resin and the crosslinking agent are adopted by the solid high softening point, melt viscosity at low temperature is higher, in the crosslinking of low temperature and coating flow flat hard, affect the surface effect.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
If the resin with low softening point and crosslinking agent can reduce the melt viscosity, the storage stability of the powder can be reduced, and it needs to be kept in cold storage, which can cause a lot of inconvenience.
Therefore, it is important to find a resin and crosslinking agent which can be suitable for powder storage to have high softening point and suitable reaction activity.
Low temperature crosslinking powder coating development direction To reduce the crosslinking temperature of powder coating, the resin from the body, crosslinking agent and catalyst, infrared radiation crosslinking, uv crosslinking, spray drying method to manufacture powder coatings powder coatings and free radicals reaction crosslinking aspects to discuss.
Thermoplastic or thermosetting powder coating whether, film-forming temperature of around 180-200 ℃, crosslinking time (10 to 20 min), which limits its can only be used for heat resistant base material, such as metals and time-consuming, relatively large energy consumption. Every 10 ℃ below the crosslinking temperature about 10% energy saving, to save energy to reduce costs, expand the range of coating powder coating, better with solvent-based coating, powder coating must be to develop in the direction of low temperature crosslinking type.
By lowering the resin itself to melting temperature, viscosity, softening point and increase the functional group increase the crosslinking degree of the resin, additives are added, apply the appropriate catalyst and other means to realize low temperature crosslinking of powder coatings. Reducing the crosslinking temperature of powder coatings can not only accelerate the production speed of automatic production line and improve production efficiency, save energy, but also make the application of powder coatings greatly increase.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
If the resin with low softening point and crosslinking agent can reduce the melt viscosity, the storage stability of the powder can be reduced, and it needs to be kept in cold storage, which can cause a lot of inconvenience.
Therefore, it is important to find a resin and crosslinking agent which can be suitable for powder storage to have high softening point and suitable reaction activity.
Low temperature crosslinking powder coating development direction To reduce the crosslinking temperature of powder coating, the resin from the body, crosslinking agent and catalyst, infrared radiation crosslinking, uv crosslinking, spray drying method to manufacture powder coatings powder coatings and free radicals reaction crosslinking aspects to discuss.
Thermoplastic or thermosetting powder coating whether, film-forming temperature of around 180-200 ℃, crosslinking time (10 to 20 min), which limits its can only be used for heat resistant base material, such as metals and time-consuming, relatively large energy consumption. Every 10 ℃ below the crosslinking temperature about 10% energy saving, to save energy to reduce costs, expand the range of coating powder coating, better with solvent-based coating, powder coating must be to develop in the direction of low temperature crosslinking type.
By lowering the resin itself to melting temperature, viscosity, softening point and increase the functional group increase the crosslinking degree of the resin, additives are added, apply the appropriate catalyst and other means to realize low temperature crosslinking of powder coatings. Reducing the crosslinking temperature of powder coatings can not only accelerate the production speed of automatic production line and improve production efficiency, save energy, but also make the application of powder coatings greatly increase.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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