What are the general steps involved in the production process of BOPP colored synthetic paper?

The production process of BOPP (biaxially oriented polypropylene) color synthetic paper generally includes the following steps:

1、 Raw material preparation and mixing

Main raw material selection: 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 filler addition: Add functional fillers such as pigments, dyes, etc. as needed to give paper specific colors and functional properties.

Additive mixing: Adding antioxidants, lubricants, fluorescent whitening agents, titanium dioxide and other additives to improve the processing performance of paper and the performance of the final product. Mix polypropylene resin, functional fillers, and various additives evenly in a certain proportion, and strictly control the proportion and quality of the raw materials during the mixing process.

2、 Plasticization and Extrusion

Plasticization: Feed the mixed raw materials into an 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. In the extruder, the raw materials are melted into a uniform melt under high temperature and high pressure.

Extrusion: Extrude molten polypropylene into thick sheets through a die.

3、 Casting and Cooling

Casting: extruding molten polypropylene melt and rapidly cooling it into regular thick sheets.

Cooling: Typically, chilled rollers and water tanks are used for cooling, with a temperature controlled between 30-45 ℃.

4、 Stretching treatment

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.

5、 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.

6、 Coating treatment

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.

7、 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.

8、 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.

9、 Packaging and Delivery

After the product passes the quality inspection, it will be delivered according to the agreed time, place, and method. Before delivery, the supplier will provide detailed packaging to ensure that the product is not damaged during transportation.

In summary, the production process of BOPP color synthetic paper is a complex and delicate process, involving multiple key steps and strict quality control. Each step requires careful operation and control to ensure the quality and performance of the final product.