Materials for making heat transfer film mainly include PVC (polyvinyl chloride) film, PET (polyester) film, PETG (modified polyester) film and OPS (oriented polystyrene) film, and their properties are as follows:
1. PVC membrane PVC membrane is one of the most widely used membrane materials at present. Its price is extremely low, its temperature contraction range is wide, and its requirement for heat source is not high. The main processing heat source is hot air, infrared ray or their combination. However, PVC is difficult to recycle and produces poisonous gas when burning, which is not conducive to environmental protection. It has been banned in Europe and Japan.
2. As a substitute for PVC film, OPS film is being widely used. It has good shrinkage performance and is also beneficial to environmental protection. Now, the product is in short supply in the domestic market. At present, high-quality OPS membrane mainly depends on imports, which has become an important factor restricting its development.
3. PETG film PETG copolymer film is not only beneficial to environmental protection, but also can adjust shrinkage in advance. However, due to the large shrinkage, it will also be limited in use.
4. PET film PET film is an internationally recognized environment-friendly heat shrinkable film material. Its technical indexes, physical properties, application scope and application method are close to PVC heat shrinkable film, but its price is cheaper than PETG film. It is the most advanced unidirectional shrinkage film at present, with its transverse shrinkage rate reaching 70% and longitudinal shrinkage rate less than 3%, and it is nontoxic and pollution-free. It is the most ideal material to replace PVC film.