What is the production process of BOPP thermal synthetic paper?

The production process of BOPP thermal synthetic paper is a complex and delicate process involving multiple steps and links. The following is a general description of the production process:

First, raw material preparation

1.Main raw materials: The main raw material of BOPP thermal synthetic paper is polypropylene resin (PP), especially polypropylene resin with high molecular weight, narrow molecular weight distribution and good processing performance. In addition, it is necessary to prepare a variety of chemicals for thermal coatings, including colorless dyes, color developing agents, sensitizers, fillers, adhesives, stabilizers and lubricants.

2.Raw material inspection: All raw materials need to undergo strict inspection before entering the production line to ensure that their quality meets the production requirements.

Second, mix ingredients

The polypropylene resin and various auxiliaries are added to the high-speed mixer in accordance with a certain proportion, and are fully stirred and mixed to ensure the uniform distribution of raw materials. This step is crucial to the quality of the subsequent extrusion cast.

Third, extrusion casting

1.Melt extrusion: The mixed raw materials are melted and extruded at high temperature by the extruder to form a certain thickness of sheet. In the extrusion process, it is necessary to strictly control the temperature, pressure and extrusion speed to ensure the quality and thickness uniformity of the sheet.

2.Quench casting sheet: The extruded molten sheet is rapidly cooled and solidified by the quench cooling device to form a BOPP base film. The quenching process helps maintain the flatness and optical properties of the sheet.

Fourth, heat sensitive coating

1.Coating solution preparation: According to the formula requirements, colorless dyes, color developing agents, sensitizing agents, fillers and other components are dissolved or dispersed in appropriate solvents to prepare thermal sensitive coating solution.

2.Coating: The thermal sensitive coating solution is evenly coated on the BOPP base film. The coating method can be applied by measuring rod coating method, scraper coating method or roll coating method. During the coating process, it is necessary to control the viscosity and coating speed of the coating solution to ensure the uniformity and thickness of the coating.

Fifth, bidirectional stretching

In order to improve the strength and toughness of BOPP thermal synthetic paper, it is usually necessary to stretch the BOPP base film coated with thermal coating. The stretching process is carried out vertically and horizontally, and needs to be carried out under certain temperature and tension conditions to ensure the quality and performance of the film.

Sixth, heat treatment and aging treatment

1.Heat treatment: The stretched film needs to be heat treated to eliminate the internal stress and improve the dimensional stability of the film. The temperature and time need to be controlled during the heat treatment process to avoid deformation or aging of the film.

2.Aging treatment: In order to further improve the performance stability of the film, sometimes it is necessary to age treatment. Aging treatment is placed at a certain temperature for a period of time to make the molecular structure inside the film more stable.

Seventh, winding and cutting

After the above treatment, the BOPP thermosensitive synthetic paper film is rewound and then cut into products of a certain width and length as required.

Eighth, inspection and packaging

Finally, the finished product quality inspection, including appearance inspection, performance testing, etc., to ensure that the product meets the quality standards. Products that pass the inspection shall be packaged and stored for sale and use.

It should be noted that there may be some differences in the production process of different manufacturers, but in general, the above basic steps are followed. In addition, with the progress of science and technology and the continuous optimization of production processes, the production process of BOPP thermal synthetic paper is also constantly improving and innovating.