The difference between PET film coating process and other processes

PET film (polyester film) is a commonly used plastic film material with excellent physical properties and chemical stability. In the production process of PET film, there are a variety of processes to choose from, of which the coating process is a common production method. This article will introduce the difference between PET film coating process and other processes.

The film coating process is a method of evenly coating the liquid polymer on the substrate through a mold or drum, and then curing it into a film by drying and cooling processes. Compared to the coating process, other common PET film production processes include extrusion processes and drawing processes. The features and differences of these processes are described below.

1. Coating process:
The film coating process is a method of evenly coating the liquid polymer on the substrate by a mold or drum, and then curing it into a film by drying and cooling processes. The characteristics of the film process are as follows:

• The production process is simple: the film process is relatively simple, the production process only needs to evenly coat the liquid polymer on the substrate, and then solidify it into a film by drying and cooling processes.
• Low production efficiency: The production efficiency of the film process is relatively low, the coating speed is slow, and it takes a longer time to dry and cool, so the production cycle is longer.
• Film thickness uniformity is better: the film coating process can achieve better film thickness uniformity, and the film thickness after coating is relatively stable.

2. Extrusion process:
The extrusion process is the method of passing the melted polymer through an extruder, and extruding it into a film through a die or an extruder head. The characteristics of the extrusion process are as follows:

• The production process is complex: the extrusion process is relatively complex, and the melted polymer needs to be uniformly extruded by the extruder, and is formed by cooling and stretching processes.
• High production efficiency: The production efficiency of the extrusion process is higher, the extrusion speed is faster, and mass production can be achieved.
• Poor film thickness uniformity: Due to the fluidity of the polymer during the extrusion process, the thickness uniformity of the extruded film is poor, and there is a certain thickness difference. 

3. Drawing process:
The drawing process is to heat the pre-prepared film at a certain temperature, and then form it by stretching and cooling. The characteristics of the drawing process are as follows:

• The production process is more complex: the drawing process is relatively complex, and the pre-prepared film needs to be heated and stretched to obtain the required film properties.
• Low production efficiency: The production efficiency of the drawing process is low, and multiple steps of processing are required, so the production cycle is longer.
• Film thickness uniformity is better: the stretching process can achieve better film thickness uniformity, and the thickness of the film can be more uniform through the stretching process.

In summary, compared with other processes, PET film has the characteristics of relatively simple production process and better film thickness uniformity. The extrusion process has the characteristics of higher production efficiency and more complex production process, while the drawing process has the advantage in the film thickness uniformity. The selection of the appropriate production process needs to be comprehensively considered according to the specific needs and requirements.