General situation and new progress of PVC heat shrinkable film development

PVC heat shrinkable film development overview and new progress Release time: 2021-02-05 Heat shrinkable film is a good film packaging material, it has the following advantages: (1) Good transparency, allowing customers to directly see the Packaged goods are convenient for customers to choose goods; (2) It is close to the shape of the goods and can be applied to the packaging of various shapes of goods, with a wide range of contents; (3) Excellent anti-theft and dust resistance; (4) Yes Pack a variety of commodities in a heat-shrinkable packaging bag to prevent individual small commodities from being lost and convenient for customers to carry; (5) Choose different resins and formulas to produce heat-shrinkable films with different mechanical strengths and functions. It is suitable for inner packaging with lower strength and lower product weight, and can also be used for transport packaging (outer packaging) for machinery and construction materials for containers that require higher strength.　　 Heat-shrinkable film first appeared in Germany during World War II. PVDC was used to pack weapons after biaxial stretching to prevent rust. Therefore, heat-shrinkable film has been used in industrial packaging from the beginning of industrial production, and then heat-shrinkable film is used for food packaging, such as: PVDC casing film for sausage packaging. Heat shrinkable film uses the energy stored in the film when the film is stretched longitudinally or transversely in a high elastic state, and uses the memory effect of the thermoplastic plastic to the shape before the bidirectional or unidirectional stretch. It can restore the function of the shape before stretching to achieve the purpose of packaging. The production method of heat-shrinkable film is to use extrusion blown film or extrusion casting method to produce thick cylindrical film or flat thick film after resin particles enter the extruder. For crystalline polymers, in order to prevent and reduce crystallization Therefore, the cooling water quenching method should be used to cool the thick film, because the crystallized thick film cannot be stretched in two directions or one direction. Stretching will destroy the crystal and reduce the mechanical strength and performance of the film. The produced thick film is reheated to the resin's T g ~ T f temperature, that is, mechanically stretched longitudinally or transversely in a high elastic state between the glass transition temperature and the melting temperature, and then cooled to become a heat shrinkable film. For amorphous polymers, such as: PVC, it can be stretched directly from the molten state to a highly elastic state, and then rolled into a heat-shrinkable film after cooling, without quenching and then heating. The heat shrinkable film label is a kind of film label printed on the plastic film with special ink. During the labeling process, when heated (about 70°C), the shrinkable label will quickly shrink along the outer contour of the container. Attached to the surface of the container, because the film itself has high transparency, the label has a bright color and good gloss. However, because it must be shrunk during use, there is a disadvantage of pattern deformation, especially for products with printed barcodes. Must go through strict design and printing quality control, otherwise the bar code quality will be unqualified after the pattern is deformed. Heat-shrinkable film labels are part of the label market and are currently undergoing rapid growth. The market share is constantly expanding. The annual growth rate is expected to be about 15%, which greatly exceeds the annual growth rate of about 5% in the ordinary label market. It has huge development potential. Become a highlight of the label printing industry. It is predicted that the domestic heat shrinkable film market will grow at a rate of more than 20% in the next 5 years.　　 The food industry is the largest market for shrink packaging. Heat shrinkable film is widely used in the packaging of various fast foods, lactic acid foods, beverages, snacks, beer cans, various alcohols, agricultural and sideline products, dry foods, and souvenirs. At present, the customer base of the shrink film label market is mainly some large fast moving consumer goods companies, such as Procter u0026 Gamble, Unilever, Shanghai Jahwa, etc., whose products are large in volume and require long-run printing. The initial investment of gravure printing is high, but the gravure printing plate has high printing endurance and relatively low cost which makes it the first choice for shrink film printing. Moreover, the graphics and text on the printing plate are recessed, so a solid ink layer, bright colors and rich layers can be obtained. Previous: The origin of heat shrinkable film