Abstract: stretch wrap films are widely used and have many characteristics and classifications. As a result, stretching around the film can be used not the same information, different processing skills produced, access to a variety of characteristics of the membrane material, satisfied with the different needs.
1. Features of stretch wrap
An excellent surround film is required to satisfy the following request.
Have the tensile strength and tearing strength enough, prevent the snap tension around the membrane in the packaging, but also has excellent resistance to hole, prevent the film is punctured around the packaging product angle, have better impact strength.
It should have outstanding tensile property and outstanding viscoelasticity. Stretch wrapped around the package, relying on a high degree of viscoelasticity, tightly wrapped in the product, no seizures, relaxation, perhaps onset of relaxation, longer time, usually requested packaging 6 months later, still able to adhere to the tension when packaging more than 60%.
When wrapping, the overlap between the film and the film should have outstanding adhesion, which is beneficial to the maintenance of the wrapping tension, to prolong the tension of the film tension, and to improve the compactness of the packing.
The elastic membrane can use long time request in -20 - 50 DEG C, function change, resistant to various changes in the environment, good weather resistance.
It has good heat sealing property, higher heat sealing strength and lower heat sealing temperature.
The price is cheap, easy to use and recovery of packaging waste granulation, easy processing.
In accordance with the above request, stretching around the film can use different information, different processing skills produced, access to a variety of characteristics of the membrane material, satisfied with the different needs.
2. Classification of stretch wrap films
According to the packaging method, stretch wrap wrap can be divided into manual stretch packaging, damping stretch packaging, pre stretched packaging.
According to material classification, the surrounding film can be divided into polyethylene film, PVC film, vinyl - vinyl film. Now a large number of production of the surrounding film, are based on linear polyethylene material, polyethylene wrapped around the film has become the main stream around the film.
According to the classification of the film structure, the surrounding film can be divided into single layer wrapped film and multi-layer wrapped film, usually as long as one side has sticky, so it is often called single-sided adhesive wrap around the film. With the film production equipment and technology progress, improve product quality, decrease product cost around the multilayer film advantage has become increasingly prominent, now has a single layer structure around the film gradually reduced.
According to the forming process is different, the surrounding film can be divided into blow molding surround film and casting surround film, casting surround film function is better.
The classification according to the use, surrounded by thin film can be divided into industrial packaging film (around such as home appliances, machinery, chemicals, building materials, packaging films, packaging agriculture around) surrounding the film and household packaging films around.