The function and production process of PVC heat shrinkable film

Heat shrinkable film is actually polyvinyl chloride, and polyvinyl chloride is a polymer of vinyl chloride. However, this kind of polymer generally contains some vinyl chloride monomer, which will migrate into food when it is heated or oil. In addition, in the manufacturing process of PVC heat shrinkable film, a kind of material-plasticizer needs to be added, and the added amount is as high as about 30%, and the plasticizer can easily dissolve into oily substances. Therefore, PVC heat shrinkable film is directly used to package meat, cooked food or greasy food, which will do harm to human body.

Heat shrinkable film PVC is a new type of environmental protection and clean packaging material, which is suitable for the outer packaging of many items, making your items more beautiful and tidy!

1. Tight sealing, good welding sealing performance.

2. Environmental protection, cleanliness, superior quality and high transparency.

3. After heat shrinkage, it is sealed and packaged, dust-proof and moisture-proof.

PVC heat shrinkable film is suitable for the packaging needs of products in various industries. It can be packaged in single pieces or small collections, or in large pallets, and can be used for heat-shrinkable packaging of stationery, toys, textiles, paper products, beverages, tongue-and-groove floors, hardware and electrical appliances, etc. PVC is made of vinyl PVC resin mixed with more than ten kinds of auxiliary materials and then inflated twice. Its characteristics are good transparency, easy shrinkage, good strength, freely adjustable shrinkage rate according to users' needs, and strong operability. PVC heat shrinkable film has good transparency and shrinkage rate of 40% ~ 60%, and its cost is low, tensile strength is large, temperature shrinkage range is wide, and the requirement for heat source is not high. The main processing heat source is hot air, infrared or the combination of both.

Heat shrinkable film is a kind of thermoplastic film which is stretched and oriented in the production process, but shrinks when heated in the use process. The thermal shrinkage of film was applied as early as 1936. At the beginning, rubber film was mainly used to shrink and package perishable food. Nowadays, the heat shrinkage technology has developed to the point that almost all kinds of commodities can be packaged with plastic shrink film. In addition, shrink packaging is also used to make shrink labels and shrink bottle caps, so that containers that are not easy to print or have complex shapes can be labeled. Recently, newer application areas have been manufactured. Production technology and characteristics The production of packaging film usually adopts extrusion blow molding or extrusion casting method to produce thick film, and then it is stretched longitudinally and transversely at a high elastic temperature above the softening temperature and below the melting temperature, or stretched in one direction only, but not in the other direction. The former is called biaxial stretching shrinkage film, while the latter is called unidirectional shrinkage film. When in use, when the temperature is higher than or close to the stretching temperature, the packaged goods will be wrapped by the contraction force.

PVC is an industrial film-coated product, which has the advantages of high elongation, good self-adhesion, high transparency and so on. It can be used for manual shrink film or machine shrink film, and can be used for centralized packaging of various goods. PVC is mainly made of several different grades of polyethylene resins, which are mixed and extruded. It has puncture resistance and good performance. The goods stacked on the pallet are shrink-packed, which makes the package more stable and tidy, and is not afraid of water. It is used in foreign trade import and export, paper making, hardware, plastics and chemicals, building materials and food industries.

Heat shrinkable film series high-pressure polyethylene is made by inflation with appropriate auxiliary materials, which is characterized by good toughness, high softness, good heat sealing property, impact resistance, strong tear resistance and not easy to be damaged. According to customers' needs, it can be processed into tubular film, L-shaped folded film and single film, and can also be processed into tubular, flat pocket and trapezoidal bags according to customers' needs.

PVC heat shrinkable film is mainly designed based on the principle of stretching orientation of high-content molecular chain. Its physical principle is to stretch the ionomer when it is in a high elastic state. When the polymer is quenched below the glass transition temperature, the molecular orientation is frozen. When the goods are packaged, the molecules will return to their original state and shrink due to the relaxation of molecular movement stress. At present, the common heat shrinkable film in the market include PVC heat shrinkable film, PVC heat shrinkable film, PP shrink film, POF co-extrusion shrink film, etc. In the big family of heat-shrinkable packaging film, POF three-layer co-extrusion heat shrinkable film is a new generation product that has gradually emerged and been accepted by people in recent years.

Heat shrinkable film is also the patron saint of building and transportation materials. It is suitable for the packaging of many products and the packaging with pallets, which is convenient for transportation and sales, easy to realize mechanization, saves labor and material resources, and can partially replace carton and wooden box packaging. It is used for packing bottled beer in heat shrinkable film instead of binding rope, so as to prevent the explosion of bottled beer from hurting people.

It has been widely used in fast food, ceramic products, tea sets, mechanical parts and other areas. Used for various PET bottled beer and beverage labels, which can reduce the process of removing labels and facilitate recycling. It is of great significance to apply the combination of heat shrinkable film and vapor phase antirust technology to replace antirust oil in machinery and hardware tools to enhance the antirust ability.