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

The production process of BOPP color synthetic paper includes the following key steps:

1、 Raw material preparation and mixing

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

Functional fillers: Add pigments, dyes, and other functional fillers 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.

Mixing: 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.

Extrusion: During the plasticization process, the raw materials are melted into a uniform melt through high temperature and high pressure in the extruder, and then extruded through the die.

3、 Casting and cooling

Casting: extruding molten polypropylene into thick sheets through a die.

Cooling: Use a cooling roller and a water tank to quickly cool into regular thick sheets, 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 and winding

Coating: Apply thermal sensitive coating, base coating, protective layer, etc. on the surface of the film. 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.

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.

7、 Cutting and time processing

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

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. Time treatment can transfer the mother material added to the core layer of synthetic paper to the surface layer to achieve the expected function.

8、 Quality inspection and delivery

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.

Delivery: After the product passes the quality inspection, it will be delivered according to the agreed time, place, and method.

These links are interrelated and jointly determine the quality and performance of BOPP colored synthetic paper. In the actual production process, each link needs to be strictly controlled and managed to ensure the quality of the final product.