shrink film

Shrink film is a film that shrinks in the longitudinal and transverse directions under the conditions of use (the action of heat and external force), thereby shrinking or sealing the package and maintaining tension on the package for a long time. This functional film is different from other functional films that use special functional masterbatches or additives to obtain specific functions. Its shrinkage function mainly depends on the characteristics of the polymer itself and the special molding process conditions.

Shrink film, including heat shrink film and stretch (cold) shrink film. The heat-shrinkable film has a heat-shrinkable function due to the directional stretching process and the unique "memory function" of polymers. hot

Shrink films are divided into two-way (longitudinal and transverse) heat shrinkable films (longitudinal and transverse shrinkage at the same time, but the shrinkage rate is not necessarily the same); unidirectional heat shrinkable (longitudinal or transverse heat shrinkable) films. Depending on the equipment selected, the heat shrinkable film can be made into a single-layer heat shrinkable film or a multi-layer composite heat shrinkable film. According to different uses, heat shrinkable film can be divided into heavy packaging heat shrinkable film (container packaging film), light packaging heat shrinkable film (small packaging film), heat shrinkable sleeve, etc. Heat-shrinkable films used in industrial production, including cylindrical films, sheet films, film bags, etc. Stretch (cold) shrink film is a sheet film. Compared with heat shrink film, it can shrink the packaging film that fastens the package without heating, also known as stretch film or stretch film. It is an extremely thin film made by applying the high elongation, puncture resistance and self-adhesiveness of low-density polymers (or adding self-adhesive polymers) that some high polymers have. Stretch shrinkable film is produced by extrusion casting or extrusion blown film method. Different equipment can be used to produce single-layer (double-sided self-adhesive) stretch-shrinkable film, multi-layer composite (single-sided

sticky) stretch shrink film. According to different uses, stretch shrinkable film is divided into stretchable shrinkable film for manual use, stretchable shrinkable film for pre-stretching machinery, anti-condensation food preservation film, etc. Shrink film is generally natural and transparent.

Commonly used plastics for making heat shrinkable films include: polyethylene (PE), polyvinyl chloride (PVC), polypropylene

Polyethylene (PP), Polystyrene (PS), Styrene Butadiene Copolymer (BS), Ethylene Vinyl Acetate Copolymer

(EVA), polyvinylidene chloride (PVDC), polyester (PET), etc. The most used material is

LDPE heat shrinkable film and rigid PVC heat shrinkable film.