ã€China Aluminum Network】 Powder coating is a powder coating composed of synthetic resin, fillers, pigments, curing agents and additives. As a new type of environment-friendly coating, powder coating has the advantages of low environmental pollution, low resource and energy consumption, low production cost, and high production efficiency. With the increasing production of powder coatings, their application areas have gradually expanded. Powder coatings are gradually replacing other solvent-based coatings and have become more promising coatings in modern society.
The production principle of a powder coating
Production principle of powder coating: Solid materials such as synthetic resins, fillers, pigments, curing agents, and auxiliaries are added to the mixer according to a certain ratio and formula to perform premixing. The premixing process should be operated under anhydrous or other solvents. The material passing through the mixer is melted at a high temperature through an extruder, completely mixed and then cooled by a cooling tablet machine to be pressed into a sheet. After passing through the pulverizer, the flakes enter the cyclone separator. After the separated coarse powder is sieved, the finished powder coating is obtained, and the fine powder is recovered. Powder coating production process does not involve any chemical reaction, it is a purely physical process.
Second powder coating quality influencing factors
1, the quality of raw materials
The quality of raw materials plays a decisive role in the quality and performance of powder coatings. Therefore, each raw material should be selected properly. The structure and properties of synthetic resins are the main factors that determine the quality of powder coatings. Synthetic resins used in powder coating materials must meet the following conditions: The synthetic resin should contain reactive functional groups; the temperature difference between melting temperature and decomposition temperature should be large, the melt viscosity of synthetic resin should be low, the melting range should be narrow, and the temperature should be above the melting point. When the melt viscosity should be rapidly reduced; synthetic resin should have good physical and chemical stability, have a higher melting point and glass transition temperature; synthetic resin should be non-toxic, light color.
Pigments and fillers as an important part of the powder coating, the chemical properties must be stable, in the powder coating production and storage process can not react with other chemical components, but also the heat and light stability. In addition, pigments and fillers are required to be uniformly dispersed in the synthetic resin. The main role of fillers in powder coatings is to increase the capacity in the components and reduce production costs. If the filler is used properly, on the basis of satisfying the basic performance of the powder coating film, it can also play a role in modification, such as the flatness and glossiness of the coating film.
Curing agents have an important influence on the film properties of powder coatings. It is an important measure for the modification of synthetic resins. The conditions to be satisfied by the curing agent include: solid at room temperature; no chemical reaction with synthetic resin and other components during production and storage; pungent odor and toxicity; colorlessness, and the like.
In order to improve the leveling properties, the glossiness or to produce a textured surface of powder coatings, it is often necessary to add auxiliaries. Special attention should be paid to the amount of additives added. Such as viscous auxiliaries or solid additives in the amount of more than 2%. The stability of the powder coating when stored deteriorates and it is very easy to agglomerate.
Select suitable raw materials to ensure the quality of the raw materials, and do not use them to make good or improper selection of raw materials.
2, formulating formula
In the formulating and selecting process of powder coating, the internal relationship of each component should be specially considered. The excellent blending of the components is the basis for ensuring the quality of the powder coating. Ignoring this point, it is difficult to obtain the desired coating effect. The synthetic resin in the powder coating composition determines the basic properties of the coating. Therefore, the first question to consider when formulating and formulating a formulation is to choose the right synthetic resin. Second, based on this, select other components and the amount of each component and ratio. Powder coating formulations should have stability and continuity. Formulation is an important factor in determining the quality of powder coatings and market competitiveness. The fine formula is the lifeline of the powder coating company and the confidentiality of the formula should be well done.
3, the choice of production equipment
The production of powder coatings is a physical process. The production equipment has an important influence on the stability of the formulation and on the quality of the powder coating. The choice of powder coating production equipment depends to a large extent on the type of product to be produced, the quality requirements and the production volume. Premixing is a front-end process for the production of powder coatings. It mixes and disperses all components to create a good homogeneous system for melt mixing. Therefore, the premixer is required to have good homogenization and dispersion capability, high shear stress, no dead angle in the mixing zone, and good sealing properties. Melt mixing extrusion is a key process for the production of powder coatings. It melts the mixed material during the extrusion process and melts it under high shear to melt the material to a suitable viscosity to ensure that the material is squeezed. Producing higher shear forces is conducive to the high degree of dispersion of the material, so that the components form a uniform system. With the use of high-efficiency extruders, it is also necessary to control the appropriate extrusion temperature. Extruder should meet the following requirements: It can make the additive evenly dispersed in the whole material; It can accurately adjust and control the temperature; The material has no dead angle in the barrel; It is easy to disassemble and clean. The crushing process is to crush the broken material particles into a suitable particle size for high pressure spraying. The size of the powder coating particles directly affects the coating film properties of the coating. The pulverizer should meet the following requirements: timely discharge of the pulverization heat generated by the movement of the particles; not only has the crushing ability, but also has an accurate particle size classification capability, and can accurately adjust the particle size of the pulverized product.
Three powder coating quality inspection technology
At present, powder coatings have been widely used at home and abroad. Its use is mainly as a protective coating and metal protection, followed by electrical insulation and anti-corrosion, but also a small amount for other functional purposes. Depending on the application of the powder coating, there are different items and requirements for testing performance. However, the detection of powder coatings is generally divided into two categories: One is to test the performance of powder coatings prior to film formation, which mainly reflects performance related to production processes, packaging, and storage. The other is to test the performance of the powder coating after film formation, which mainly reflects the physical and mechanical properties, corrosion resistance and the like related to the use requirements. In order to make the detection structures comparable to facilitate exchanges and trade, many countries have established uniform testing methods and testing standards. Such as the United States ANSI/ASTM standard, the International Electrotechnical Commission's IEC455-2 standard, China's powder coating implementation of GB6554-86 standard. The detection of powder coatings is an effective guarantee of their quality. Mastering the powder coating inspection technology is extremely important for the powder coating research, production and application departments. Only by understanding the detection technology of powder coatings can we better select and adjust raw materials and formulas, reasonably control and adjust production processes, and better stabilize and improve the quality of powder coatings.
Four conclusions
As a new type of environmentally friendly coating, powder coating has a bright future. Powder coating production process is simple, easy to automate production, to a large extent, saving resources and energy, ensuring the health of operators and improving labor productivity. The development of powder coatings has undoubtedly made an outstanding contribution to society.
application: viation,automotive, motorbike, bicycle, automatic equipment, household appliance, medical device ,toy, telecommunication,computer, instrument and meter,furniture, electric tools,mold and other industries
China Torsion Spring,Garage Spring manufacturers, welcome Helical Torsion Spring,Double Torsion Spring purchasers from worldwide to visit our site.
Torsion Spring,Garage Spring,Helical Torsion Spring,Double Torsion Spring,Torsion Spring Manufacturer
Shenzhen Lanejoy Technology Co.,LTD , https://www.wire-spring.com