Types of functional powder coatings
The powder coating is a new type of solvent-free 100% solid powder coating. Has a solvent-free, non-polluting, recyclable, environmentally friendly, saving energy and resources, and reduce labor intensity and the film mechanical strength.
The coating form and the formation of the coating solids of up to 100%, because they do not use solvents, thereby reducing environmental pollution, conserve resources and recyclable characteristics.
The functional powder coating is a special function, surface coating materials to provide for special purposes. It not only can play the traditional role of protection and decoration, and also gives the material a variety of specific functions, including insulation, conductive, anti-pollution, heat, flame retardant, radiation protection and other functions.
Development and production of functional powder coatings has just started, still lags far behind with foreign advanced level. Commonly used functional powder coatings generally have the following types:
Insulated Powder Coatings
Insulation powder coating A special coating is used for motors, electrical and electronic components, in addition to the protection of the general powder coatings, decorative properties, but also has good electrical insulation properties.
Epoxy resins are excellent raw materials for manufacture of insulating powder coating.By changing the type of curing agent, or add a special modifier and with good insulation and heat resistance of fillers to adjust the curing rate, obtained from very soft, flexible, very hard, wear a variety of coating to adapt to different insulation conditions. In recent years, with the exception of epoxy powder coating, polyurethane powder coating, powder coating of polyimide, acrylic powder coatings, etc. are also constantly develop and use.
Conductive powder coatings
The conductive powder coating is applied to the non-conductive substrate, so that it has certain conduction current and the elimination of the electrostatic capacity of functional coatings. Such coatings are mainly two types: the blending type and the intrinsic type.
Blended powder coatings are insulating polymer coating film forming materials, the formation in which the incorporation of conductive fillers. Conductive filler, metal powder, such as silver, nickel, zinc, aluminum, etc.; non-metallic powder, such as graphite, carbon black; metal oxides such as zinc oxide, antimony oxide. The binder Select vinyl resins, polyester resins, polyamide and epoxy resin.
The intrinsic conductive polymer is the polymer itself is conductive, the current class of polymer is still in theory and research stage, there is no practical application.
Anticorrosive powder coating
Currently using such coatings epoxy phenolic anti-corrosion powder coating it with epoxy resin and phenolic resin-based film-forming substances, both cross-linking formation of the coating. This type of paint used in the epoxy is generally used in the polymer species of molecular weight of 1400,2900 and 3570. Epoxy resin itself, adhesion, flexibility and alkali resistance and good, and phenolic resin with excellent acid, solvent, heat, humidity cold performance are combined to become anti-corrosion materials ideal types. Weaker reactivity between the epoxy and phenolic resin coating film curing temperature required at higher conditions, by adding appropriate amount of imidazole catalyst to reduce the curing temperature.
Heat resistant powder coating
Heat resistant powder coating can long withstand temperatures above 200 ℃, good film, and make the object of protection in high temperature environment to function properly.
From the mechanism in terms of polymer thermal stability, heat resistance of the polymer depends on its molecular structure. Thus, increase the force of intermolecular interaction by the introduction of larger or more polar side groups in the main chain, thereby improving the thermal stability of the polymer. Another way is to improve the heat resistance of powder coatings by adding heat-resistant pigments and fillers in the polymer. Commonly used in pigments, fillers are aluminum powder, mica powder, stainless steel powder, cadmium powder, silica. At present, the heat-resistant powder coating is still silicone powder coatings based. This coating the main direction of future research development capability at higher temperatures and has good film forming and construction performance of high-temperature resin as base material of the heat-resistant coatings, as well as research can significantly improve the performance of a variety of base material in high temperature conditions pigments, fillers, new varieties.
Decorative powder coatings
Decorative powder coating is characterized by coating the surface of the clear appearance of the pattern to the coating objects are beautiful and colorful appearance.Powder coating formation mechanism of pattern and solvent-based paints are very different, both pattern forms are also different. The powder coating use its melting characteristics of the texture effect, pattern shapes and sizes, recipe mix, preparation technique and powder particle size.
Formula combination of synthetic resin, curing agents, leveling agents, pigments and various additives, is the main factor in the formation of patterns. Developed ways to have the following main ideas:
- use of incompatible polymers to produce a flow state, the formation of three-dimensional sense of pattern;
- different curing rate of the curing agent, due to the difference in leveling speed to form a suitable wrinkles;
- With different fillers, resulting in powder coating leveling, gloss and hue differences, resulting in the texture effect;
- different granularity and different shade of metallic pigments in the coating in a different position, different angles, resulting in differences in gloss and hue.
Flame retardant powder coating
High polymer flame retardant restricted, to improve the flame retardancy of polymers is of practical significance in many areas of application. The flame retardant powder coatings for fire and fire-retardant insulation function. With the rapid development of modern electronics and appliances industry, the requirements for fire-retardant coating is more urgent. The main varieties of this coating is epoxy powder coating.
The functional powder coating is a special kind of functional materials play an increasingly important role in many areas of science and technology, defense, industrial and agricultural. Of gap with foreign countries in such products developed large, we must intensify efforts to develop and to develop a functional effect of significantly superior overall performance, low cost, painting the functional powder coatings to meet the needs of national economic development needs.