For extruders manufacturing thermosetting powder coatin […]
For extruders manufacturing thermosetting powder coatings, when changing the resin type or color type of the coating, it must be cleaned to prevent interference between the powder coating varieties and ensure the quality of the products produced. When the cleaning of the extruder is incomplete, the most obvious effect is on the color of the powder coating, which can be directly observed; in addition, the art powder coating without leveling agent was previously produced and the extruder was not cleaned. When reproducing a high-gloss powder coating, due to the interference of the aforementioned materials, the coating film of the product produced later is liable to cause shrinkage cavities and the like. Therefore, it is very important to clean the machine thoroughly when changing the type of paint resin and color. There are many cleaning methods for extruders. The following editors will introduce two methods for you:
Resin cleaning method
This method uses a resin such as polyester resin or epoxy resin cleaner. This method is usually used after cleaning a new device or extruder for a period of time, because some materials remain on the screw or barrel to adhere, the extrusion speed of the material becomes slow, and the color difference is very large. Variety of discoloration is very large. This method can be used. After washing the resin, the powder of the powder coating to be produced is further cleaned without adding a curing agent or cured resin, and when the extrudate is considered clean, it can be officially put into production. If the color difference of the powder coating type changes little and the thorough cleaning time is not too long, only resin cleaners for powder coatings are produced. In order to increase the friction of the resin, it is beneficial to remove the machine, and some fillers can be added for cleaning.
Non-resin removal method
This method uses rice, corn, sawdust, toilet paper, etc. which have a certain friction and are easily crushed. When the extruder is heated to the normal extrusion temperature, the friction between the screw and the screw is removed. The powder coating gel adheres to the surface of the screw and barrel. Experience shows that the outer shell of rice has high hardness and high friction, and the cleaning effect is better. After cleaning the machine in this way, the screws must be opened to check the condition of the machine. Under normal circumstances, before producing an official product, the powder must be re-washed with powder coating according to the above method.