Tips for the use of additives in powder coatings

China Coatings network
News:
1, powder coating additives and resin compatible
this is the first thing to pay attention to when selecting additives.
powder coating
must be stored in powder
coating
for long-term stability in order to achieve its due effectiveness. Therefore, the general use of additives should be compatible with epoxy, polyester, acrylic and other resins. The method used to compare the
of powders
coating additives and resins is usually based on their structural similarity. For example, the leveling agent is the main additive in the production of powder coating, which can reduce the difference in surface strength of the coating film, play the role of coating ionization and elimination of shrink holes, so that the cured coating film to obtain a smooth gloss of the surface. When used, there are carrier additives such as E-12 carriers can not be used with pure polyester system formulation, and, each company produces a different level of the applicable system, which requires powder manufacturers to find suitable resin to match, the same is true of the brightener. As usual, the B68 chemical anti-lighting agent containing ringand polysalt is only applicable to epoxy systems, if used in other systems, not only lose its due effect, but also bring negative effects to the coating film.
Some powder coating additives in the formulation design, should be considered because the production process conditions are more demanding, may be high temperature, low temperature, high-speed shearing and other conditions, resulting in the decomposition of powder coating additives, volatilization and failure, resulting in formula failure. Such as some pattern powder coating additives, can not be extruded by the extruder together with the base material, but then added to the finished powder, only in this way can show its due pattern. Because in the process of extrusion and melting, the pattern aid has been pre-reacted to complete, resulting in no pattern or produce different pattern size, different feel, different three-dimensional sense and other phenomena.
In the process of two or more additives and substations, in order to give full play to the effectiveness of additives, they must be fully dispersed in the powder coating substation, and can be combined with the substation in different feeding order.
experienced technical engineers know that the sequence and process conditions at each step are very important when a variety of powder coating additives are mixed with the base material or added to the finished product, which directly affects the mixing effect and the performance of the coating film.
some powder coating additives in addition to playing a major role, but also have a dual or multiple role. As a result, we have to consider a combination of recipes when designing them, such as adjusting the amount used in the formulation or simplifying the formulation. For example, zinc oxide is a kind of party chemical, it can replace a part of the
titanium dioxide
white pigment; At the same time has a certain degree of conductivity used in the need for anti-static or conductive occasions; It also has the function of shielding ultraviolet rays, especially the UV light in the range of 240-380/m has better protection ability; Of course, it also has anti-mold, sterilization effect, improve the paint properties containing carboxyl-based group resin, etc. It can be seen that the choice of an effective additive is to fully understand its various functions.
synergy effect of powder coating additives refers to the synergy effect of two or more additives when used together properly. The opposite of synergy, of course, is confrontation. For example, carbon black and sulfur phenol antioxidants in the pure polyester outdoor powder coating, there is an excellent synergetic antioxidant effect, but in conjunction with bit-resistor or phenolic antioxidants, the original stability effect of the coating film is weakened by the adverbial effect.
we know that some powder coating additives, while playing their normal role, sometimes have to have a negative effect on some of the properties of powder coatings. This is closely related to the dosage of additives. At present, there is a low temperature curing agent on the market, which enables powder coatings to be cured into film within 120 degrees C/30min, which is of course what we need. Because such low curing conditions will bring great economic benefits, but also to some materials can not be baked at high temperatures to provide applications, greatly expanding the application of powder coatings. However, as far as we have done, we know that the addition of this low-temperature curing agent will have a greater impact on the adhesion of the coating film. These are the powder coating additives that we should fully understand when designing our formulations.
powder coating additives are often restricted by the end-use of powder coating coating, different powder coating varieties of powder coating additives color, odor, anti-pollution, durability, electrical, heat, cold resistance and so on.
are familiar with powder coatings know that the general powder coating additives in the powder coating formulation system accounted for a small proportion, but very expensive, so sometimes, the price is also an important factor to measure its use. Usually, we can select several different suppliers of the same type of products for comparative testing, in the same effect, choose low-cost products. Many domestic manufacturers produce powder coating additives, generally can be compared with similar products produced abroad.