Film calendering

The raw and auxiliary materials required for film calendering are mixed and masticated evenly under a certain temperature and pressure, and then put into a calender composed of two or more rollers rotating in opposite directions. The forming method of slot extrusion into a continuous film or sheet of predetermined size is called calendering. The calendered film thickness is determined by the roller gap and subsequent draw ratio.

Calendered film, including soft PVC calendered film, hard PVC calendered film (sheet), polyethylene

Sheets for vinyl calcium-plastic corrugated boxes (surface sheets, corrugated sheets), may also include calendered composite materials, such as plastic floor leather, plastic wallpaper, artificial leather, etc.

There are many production equipment and production processes used in film calendering. This book only briefly introduces the production technology of soft PVC calendered film.

Features of film calendering

Calendering of film generally includes three parts: preparation and mixing of raw and auxiliary materials, calendering into

type, calendering follow-up treatment, etc.

(1) Preparation of raw and auxiliary materials and acceptance of mixing raw and auxiliary materials, resin screening, powder refining, material

Material metering, high-speed (hot) mixing, cold mixing, kneading, feeding to the calender, etc.

(2) Calendering Calendering, traction, cooling, cutting, coiling, etc.

(3) Calendering post-processing embossing, printing, expanding (stretching tentering).

Calendering post-processing items are determined by the use (or function) of the film, and the calendering and subsequent processing of the film

The principle is that continuous film calendering on the same production line has the following characteristics compared with extrusion molding:

1) The quality of the film is stable, the thickness is uniform, and the deviation is small;

2) The molding equipment has a high degree of automation, which can realize the linkage operation of the production line;

3) The line speed of film production is high, the processing capacity is large, and the output is high;

4) It is especially suitable for the molding and processing of heat-sensitive plastic (such as polyvinyl chloride) films;

5) The width of the film is limited by the width of the calender roll (generally the maximum is 4m), even if the film is stretched and tented, its maximum width is about 6m;

6) There are many calendering and forming processes, the production line is long, the equipment is huge and the one-time investment cost is high. Equipment maintenance

The maintenance requirements are also high, which limits the production development to a certain extent.