The type of powder coating come to understand it!

The type of powder coating come to understand it!

1. Thermoset type

Thermosetting powder coating refers to the thermosetting resin as a film forming material, adding the curing agent of crosslinking reaction after heating to form an insoluble and insoluble texture of hard coating. No matter how high the temperature is, the coating will not soften like the thermoplastic coating, but can only decompose. Because the resin used in the thermosetting powder coating is a prepolymer with low polymerization degree and low molecular weight, the coating has good leveling property and good decoration, and the prepolymer with low molecular weight can form a network of cross-linked macromolecules after curing, so the coating has good corrosion resistance and mechanical properties. Therefore, the development of thermosetting powder coatings is particularly rapid.

(1) Epoxy powder coating. Due to its excellent adhesion with metal, corrosion resistance, hardness, flexibility and impact strength, it is the first variety used in thermosetting powder coatings. The preparation of Epoxy powder coating is composed of Epoxy Resin, curing agent, pigment, filler and other auxiliaries. The contribution of these components to the performance of the powder coating is mutually restricted and affected, and a suitable formula is actually the result of the coordination of various components.

(2) Polyester powder coating. Compared with other types of powder coatings, polyester powder coatings have unique properties. It is better than epoxy resin in weather resistance and UV optical rotation resistance [2]. In addition, because the polyester resin has polar groups, the powder rate is higher than the epoxy resin, the baking process is not easy to yellow, high gloss, good leveling, full paint film, light color and other characteristics, so it has a good decorative. Generally used in refrigerators, washing machines, vacuum cleaners, instrument shells, bicycles, furniture and other fields.

(3) acrylic powder coating. Acrylic resin powder coatings are thermoplastic and thermosetting. The advantages of thermosetting acrylic resin powder coating are excellent weather resistance, color retention, pollution resistance, strong metal adhesion, excellent film appearance, suitable for decorative powder coating.

2. Thermoplastic

Thermoplastic powder coatings began to appear in 1950, it melts at spray temperature and solidifies into a film when cooled. Due to the simple processing and spraying methods, powder coatings only need to be heated and melted, levelled, cooled or extracted to form films, without the need for complex curing devices. Most of the raw materials used are common polymers on the market, which can meet the requirements of performance under most conditions. However, there are also some shortcomings, such as high melting temperature, low coloring level, and poor adhesion to the metal surface. However, the commonly used thermoplastic powder coatings still show some unique properties, among which polyolefin powder coatings have excellent solvent resistance; Polyvinylidene fluoride coatings have outstanding weatherability. Polyamide has excellent wear resistance; PVC has a good price/performance ratio; Thermoplastic polyester powder coating has the advantages of beautiful appearance and high artistic quality. These characteristics make thermoplastic powder coatings occupy a large proportion in the coatings market.

(1) Polyvinyl chloride powder is one of the cheapest polymers produced on an industrial scale. It has excellent solvent resistance, good corrosion resistance to water and acid, impact resistance, salt spray resistance, can prevent food contamination and electrostatic spraying has high insulation strength. Mainly used for painting metal mesh board, steel furniture, chemical equipment and so on.

(2) Polyethylene powder coating has excellent corrosion resistance, chemical resistance and excellent electrical insulation and ultraviolet radiation resistance. The disadvantage is that the mechanical strength is not high and the adhesion to the matrix is poor. It can be used in chemical tank, impeller, pump, pipe inner wall, instrument shell, metal plate, refrigerator inner screen board, auto parts and so on.

(3) Nylon powder coating. Nylon (Nylon) is also known as polyamide, because the N atom of the chlorine group on the molecular chain and the hydrogen atom on the adjacent chain segment are easy to form hydrogen bonds, so the melting point of polyamide resin is generally higher. Nylon has the advantages of high mechanical strength, impact resistance, hardness, wear resistance and small friction coefficient, low dust absorption, etc., can be used for special requirements of the parts. For example, it is used in water pump impeller, textile machinery parts, diesel engine starting piston parts, machine sailing propeller impeller, automobile wheels, motorcycle support, agricultural machinery, construction and sports equipment. In addition, due to the resistance of nylon to salt water and the inertia of mold and bacteria, it is suitable for manufacturing coating soaked in seawater or in contact with seawater, while nylon powder coating is non-toxic, tasteless, not corroded by mold, will not promote bacterial growth, it is suitable for spraying parts of the food industry, drinking water pipes and food packaging.

(4) fluorine resin powder coating. There are many kinds of fluoropolymers that can prepare powder coatings, such as polytetrafluoroethylene (PTFE), polytrifluorovinyl chloride (PTFCE), polyvinylidene fluoride (PVDF) and so on. Polytetrafluoroethylene melting point is as high as 327 ° C, can be used in the range of -250 ~ 250 ° C for a long time, in addition to excellent corrosion resistance, even in king water is not corroded, excellent dielectric properties, very low friction coefficient and self-lubrication, so known as "plastic king" said. It is widely used in petroleum, chemical anti-corrosion coating, sealing, bearing lubrication materials, electronic and electrical materials, ship launching guide rail and non-stick coating. Polytrifluorochloroethylene is cheaper than PTFE, the processing temperature can be reduced, the coating can be used for a long time below 130 ° C, the ability to resist alkali and hydrogen fluoride corrosion is better than acid-resistant enamel, and the ability to resist hydrochloric acid, dilute sulfuric acid, hydrogen chloride and chlorine gas corrosion is better than stainless steel equipment. It has been widely used in chemical plants, pesticide factories, pharmaceutical factories, detergent factories and other anti-corrosion equipment. The biggest advantage of polyvinylidene fluoride powder coating is excellent weather resistance, high resistance to degradation in outdoor exposure, and does not absorb dust, it is easy to maintain the original luster. 5 chlorinated polyether powder coating. Chlorinated polyether has excellent chemical stability, the film has good corrosion resistance and dissolution resistance to a variety of acids, bases and solvents, the chemical stability is second only to polytetrafluoroethylene, and the mechanical and frictional properties are also very good. Chlorinated polyether powder coating is mainly used in chemical equipment, pipeline lining, instrument equipment shell and so on. Its disadvantage is that it has poor adhesion with metal. The adhesion with metal can be improved by adding additives.

(5) latex powder coating. Emulsion powder is made by spray drying emulsion, most of which are vinyl acetate copolymers. The coating produced by latex powder is called latex powder coating. It is the most environmentally friendly coating in the current wall coating.