What is the main process for producing colored thermosensitive synthetic paper?

The main process of producing colored thermosensitive synthetic paper includes the following key steps:

1、 Raw material preparation

Main raw materials: Polypropylene (PP) resin, especially isotactic polypropylene, is mainly used, and its content needs to reach a high standard (such as 95%~97%) to ensure the tensile strength and physical properties of the film.

Functional fillers: Add functional fillers such as pigments, dyes, etc. as needed to give paper specific colors and functional properties.

Additives: including antioxidants, lubricants, fluorescent whitening agents, titanium dioxide, etc., to improve the processing performance of paper and the performance of the final product.

2、 Raw material mixing

Mix polypropylene resin, functional fillers, and various additives evenly in a certain proportion. The mixing process requires strict control of the proportion of raw materials and mixing quality to ensure the performance of the final product.

3、 Plasticization

Send the mixed raw materials into the extruder for plasticization. The processing temperature of the extruder is generally around 250 ℃, and the specific temperature is adjusted according to the temperature resistance of the raw materials and the performance of the extruder. During the plasticization process, the raw materials undergo high temperature and high pressure in the extruder, melting into a uniform melt.

4、 Cast piece

Squeeze the melted polypropylene melt through the die into thick sheets and rapidly cool them into regular thick sheets. The cooling process usually uses chilled rollers and a water tank, with a temperature controlled between 30~45 ℃.

5、 Stretching

Longitudinal stretching: The casting sheet is subjected to longitudinal stretching treatment, with a stretching ratio generally between 4.5 and 5.5. During the stretching process, it is necessary to control the temperature of the preheating zone, stretching zone, and shaping zone to ensure the uniformity and tensile strength of the film.

Lateral stretching: The casting sheet is subjected to lateral stretching treatment, with a stretching ratio generally between 9 and 10. Horizontal stretching also requires controlling the temperature and stretching speed of the preheating zone, stretching zone, and shaping zone to achieve bi-directional stretching of the film.

6、 Surface treatment

Perform corona treatment or other surface treatments on the stretched film as needed to improve the surface tension of the film and enhance the adhesion of the coating layer.

7、 Coating

Coat the surface of the film with a thermosensitive coating, a base coating, and a protective layer. The coating process requires strict control of the composition, concentration, and coating amount of the coating liquid to ensure the performance of the final product.

8、 Roll up and slitting

Roll up: Roll up the coated film into a uniform large roll. During the winding process, it is necessary to control the tension of the contact roller and pressure roller to maintain the flatness and tightness of the large film roll.

Slitting: Cut large film rolls into appropriate sizes according to customer requirements. The slitting process requires strict control of slitting accuracy and edge quality.

9、 Timeliness processing and quality inspection

Aging treatment: The sliced film is subjected to aging treatment, usually completed within 24-48 hours, to improve the physical properties and stability of the film.

Quality inspection: Conduct quality inspection on the aged film, including appearance quality, physical properties, printing effect, etc., to ensure that the final product meets relevant standards and customer requirements.

In summary, the production of colored thermosensitive synthetic paper is a complex and delicate process that requires strict control of process parameters and quality requirements at each stage to ensure the performance and quality of the final product.