Winding film, also known as stretch film, heat shrinkable film, the earliest PVC winding film in China with PVC as the substrate, DOA as a plasticizer and self-adhesive. Due to environmental protection problems, high cost (relatively large PE ratio, small unit packaging area), poor stretchability and other reasons, it was gradually eliminated in 1994~1995. PE stretch film first uses EVA as a self-adhesive material, but its cost is high and has taste, and then developed with PIB and VLDPE as self-adhesive materials, and the substrate is mainly LLDPE, including C4, C6, C8 and metallocene PE (MPE).
Form of use:
1. Sealed packaging
This packaging is similar to shrink wrapping, the film wraps the tray around the tray, and then two hot grippers heat seal the film at both ends together. This was the earliest form of wrapping film, and more packaging forms were developed as a result
2. Full width packaging
This kind of packaging requires that the film width is enough to cover the tray, and the shape of the tray is regular, so it is suitable for the film thickness of 17~35μm
3. Hand packing
This packaging is the simplest type of wrapping film packaging, the film is mounted on a rack or handheld, turned by the tray or the film rotates around the pallet. It is mainly used for repackaging after the wrapped pallet is damaged, and ordinary pallet packaging. This kind of packaging speed is slow, suitable film thickness of 15~20μm;
4. Stretch film winding machine packaging
This is the most universal and widespread form of mechanical packaging, which consists of a tray rotating or a film rotating around a pallet, and the film is fixed on a bracket to move up and down. This packing capacity is very large, about 15~18 trays per hour. The suitable film thickness is about 15~25μm;
5. Horizontal mechanical packaging
Different from other packaging, the film rotates around the article, which is suitable for long goods packaging, such as carpets, boards, fiberboard, special-shaped materials, etc.;
6. Packaging of paper tubes
This is one of the latest uses of wrapping film, which is better than the old-fashioned paper cylinder packaging with wrapping film. The suitable film thickness is 30~120μm;
7. Packaging of small items
This is the latest form of wrapping film that can both reduce material consumption and storage space for pallets, which was first introduced in 1984 abroad, and only a year later, many such packaging appeared on the market, this packaging form has great potential. Suitable film thickness 15~30μm;
8. Packaging of tubes and cables
This is an example of the application of wrapping film in a special field, where the packaging equipment is installed at the end of the production line and the fully automatic stretching film can both replace the strap binding material and serve as a protective effect. The applicable thickness is 15~30μm.
9. Stretched form of pallet mechanism packaging
The packaging of stretch film must be stretched, and the stretching forms of pallet mechanical packaging are direct stretching and pre-stretching. Pre-stretching is divided into two types, one is roller pre-stretching and the other is electric stretching.
