What are the steps of the production process of BOPP synthetic paper?

The production process of BOPP (Bidirectional polypropylene film) synthetic paper mainly includes the following steps:

1. Raw material preparation

Main raw material: polypropylene resin, requiring a high molecular weight, narrow molecular weight distribution and good processing properties.

Additive addition: In order to improve the performance of the film, it is also necessary to add some additives, such as antioxidants, antistatic agents, smoothing agents, etc.

2. 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.

3. Extrude the cast

The mixed raw materials are melted and extruded by the extruder to form a certain thickness sheet. This process requires strict control of temperature, pressure and extrusion speed to ensure the quality and thickness uniformity of the sheet.

4. Two-way stretch

Longitudinal drawing: multi-roll drawing method, after preheating, stretching and cooling steps. The preheating temperature is usually 130-135 ° C, the tension and temperature need to be controlled during the drawing process to avoid the phenomenon of sticking rollers or cold pulling, and the cooling process makes the crystallization stop quickly and fixes the orientation of macromolecules.

Transverse drawing: carried out in the tenter, including preheating section, stretching section and heat setting section. The preheating temperature is close to the melting point, usually at 160-165 ° C, and the transverse drawing ratio is less than the longitudinal drawing ratio, generally between 4-6. The purpose of heat setting is to reduce the internal stress and obtain a stable size.

Step 5 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.

6. Roll and cut

After heat treatment, the film is rewound and cut to obtain a certain width and length of BOPP film products.

7. Other treatments (optional)

Depending on the specific needs, subsequent processing steps such as corona treatment and printing may also be included to improve the surface properties and aesthetics of the film.

Matters needing attention

In the entire production process, each process parameter needs to be strictly controlled to ensure the quality and performance of the product.

At the same time, it is also necessary to pay attention to the safety and environmental protection issues in the production process to avoid harm to the environment and personnel.

With the continuous progress and application of science and technology, BOPP's production process is also constantly improving and innovating to adapt to market changes and enhance product competitiveness.

To sum up, the production process of BOPP synthetic paper is a complex and fine process, involving the control and adjustment of multiple links and process steps.