1. Features of double (multi) component coatings
Two (multi) component coatings include various catalytic curing coatings, amine curing epoxy polyester, polyurethane coatings and acid curing amino resin coatings. Their characteristic is that in order to ensure storage stability, the two (or more) main components of the paint need to be placed separately. Because as long as they are mixed together in an appropriate proportion, a chemical reaction will occur soon, releasing heat and curing, so that the paint can no longer be used, so it is only mixed during the spraying process. The various components of ordinary coatings (also known as one-component coatings) can be mixed in advance and can maintain storage stability.
2. Application of double (multi) component coatings
The double (multi) component paint is the same as the single component paint in that after spraying, it can form a decorative and protective coating on the surface of the object to be coated. The difference is that the double (multi) component paint can not only Form a thin coating, and some can also form other forms of products, such as spraying multi-component polyester coatings on the network skeleton of glass fibers, initially forming a coating on its surface, but continuing to spray Form a thicker layered structure, then lay another layer of glass fiber mesh on top, and continue to spray multi-component polycarbonate coatings, and finally form a glass fiber reinforced polyester structural product, which is commonly referred to as FRP. The two-component coating can also be sprayed on various substrate materials to fill holes, fix the various parts in the assembly, and form a sealed structure. If the double (multi) component paint is sprayed on a mold with a fixed shape, it can be turned into various molded products. This characteristic of two (multi) component coatings makes it widely used in aerospace industry, marine industry, construction industry and electronic industry. For example, the foamed material formed after spraying with two-component paint can play a good role in heat insulation, sound insulation, buffering and shock absorption in the equipment, and the formed laminated material can be used as a decorative surface for furniture and buildings. The formed packaging material can well seal and fix various electrical components and mechanical parts.
3. Spraying equipment for double (multi) component coatings
The types of equipment used to spray two-component coatings are similar to those used for spraying ordinary (single-component) coatings, and can be sprayed with air atomization or high-pressure atomization. If you use ordinary paint spraying equipment for spraying, you should pay attention to mixing the original separate paint components in proportion before use, and then use them immediately, because the shelf life of the mixed two-component paint is very short.
short, and the remaining coating cannot be used once it has cured. The amount of paint sprayed needs to be calculated to avoid unnecessary waste. Therefore, ordinary spraying equipment is used only in the case of small batch spraying, and in most cases, special spraying equipment for two-component coatings is used, which is obtained by slightly improving ordinary spraying equipment. Since the two components of the paint are conveyed by their own conveying pipelines during spraying, there are correspondingly two inlets and two nozzles on the two-component Spray Gun, and the two paint components have their own power supply and conveying systems respectively. The two components are mixed in the Spray Gun and further atomized and dispersed evenly during the spraying process.
A two-component air spray equipment is shown in Figure 4-52. Paint is fed from a pressurized paint tank through a paint hose to the Spray Gun. Another component (curing agent) of the paint is dissolved and dispersed into a liquid state with a volatile solvent (such as ethyl acetate, etc.), and then sucked up through a siphon tube and mixed with compressed air by means of the siphon effect of high-speed flowing air. . Outside the mouth of the air Spray Gun, the curing agent is mixed with the paint and sprayed onto the surface of the workpiece, and a chemical reaction occurs in the formed coating to cure and form a film.
According to different application purposes, the requirements for the atomization effect of the equipment are also different. If a coating film with good decorative and protective effects is to be formed, it is the same as the one-component paint spraying, and a good atomization effect is required. When used to form other forms of products, the requirements for the atomization effect are not high, and even no atomization is required. The following is a further introduction to two-component spraying combined with two practical applications.
