Radiation resistant food plastic packaging film hollow plate production line

日期:2021/4/2 8:48:42 / 阅读: / 来源:本站

Radiation resistant food plastic packaging film hollow plate production line


 Hollow plate production line www.handern.com
 In recent years, the work of radiation sterilization and preservation of food in China has made great progress. The Radiation Research Institute of Wuxi Light Technology University has used y-ray irradiation for fresh keeping since 1986. The storage period of fruits irradiated by y-ray has been greatly extended. For example, citrus can be stored in May of October without mildew and deterioration. However, it is not prevented from volatilization and drying of water The quality of the orange is greatly improved after being irradiated after the plastic film packaging. The vegetable company of Kaifeng City of Henan Province has set up a nuclear energy irradiation plant for food in Kaifeng City. It uses 2-ray of cobalt 60 to process and produce various kinds of dry and fresh vegetables, melon and fruit, beverage, medicine, meat, fish and other foods, which has good economic and social benefits. The plastic packaging film they provide has the following requirements: first, it is non-toxic; secondly, it can withstand the irradiation of 10kGy rays without degradation and deterioration; third, it has good moisture resistance; fourthly, it has good tear resistance and tensile strength; fifth, it can withstand the temperature of 120-110c. Hollow plate production line www.handern.com
It has been pointed out that plastic packaging materials will produce organic low molecular compounds with various components under the radiation of high energy electrons accelerated by electron accelerator. Among them, acetaldehydric acid, toluene, carbon hydride, etc., these substances have a certain odor, which will affect the color and flavor of food. The common LDPE inner sealing material has better odor than LLDPE. At present, the irradiation resistant and bactericidal packaging film using LLDPE as bag is more ideal. Hollow plate production line www.handern.com
When choosing the materials for packaging fresh fruits and vegetables, on the one hand, the radiation resistance of the materials, and the preservation function of the materials, the cells of fresh food in the low breathing "hibernation" state for a long time can keep fresh and not rot. Therefore, the plastic film with certain permeability and moisture permeability is conducive to the accumulation of CO2 gas and the decrease of oxygen in the bag. When the air in the bag is O; the gas decreases to 2% due to the respiration of fresh food cells, and co increases to more than 7%, the food in the bag can be kept fresh for a long time. Too much oxygen can accelerate the respiration of fresh food cells, forming "over ripening" and rot. After the irradiation of) rays, there will be two changes in polymer materials. One is the cross-linking between molecules. The polymer which belongs to the linear line becomes a network structure due to the cross-linking of chemical bonds, which improves the heat resistance, bath resistance, mechanical strength and rigidity of polymer materials, but the low temperature resistance becomes poor, and the brittleness increases and the softness decreases. The other is that the 7 molecules have been degraded, The degradation results showed that all the properties were deteriorated.
Irradiation can kill insects and bacteria, but to some extent, it also limits the activity of enzyme. Therefore, food that needs the function of enzyme bark should pay attention to the dose. The materials that can accept 50kg Gy irradiation are PS, PA, LDPE and hdpppvc, but PP can not be used for irradiation packaging. PP is irradiated in the presence of O2, and it can degrade and brittle rapidly. In 1966, the United States approved 11 kinds of radiation food packaging materials, 19 in 1972, some of which were plastics, and in 1976, the FDA approved PE, pet, chloroacetate resin and nylon 6 as irradiation food plastic packaging materials. Recently, it also approved ethylene butene copolymer, vinyl chloride vinylidene chloride copolymer, PS, plasticized PVC and nylon 11 as irradiation food plastic sentence base materials.
The practice shows that the three-month composite bag with nylon 6 as outer layer, aluminum foil as the intermediate layer and inner layer as MDPE or pet/al/mdpe is a good radiation food packaging material. The composite bag with this structure, the annual output of 400000 in the United States in 1970s, 40000 kg of beef packaged in vacuum irradiation, only the failure rate of less than 0.01%, and the bactericidal beef irradiated by 40c-50c for 47-7lkgy is safe. For various kinds of fish packing, the suitable packing materials are k coated nylon 11.nylon 11 and aluminum box coated nylon 11 as irradiation sterilization packaging materials, but not suitable for PE and PP films. For fresh pork, it is suitable to use PVA based composite membrane as radiation sterilization packaging material, such as pe/pva/pe, or pp/pva/pe, which remains fresh for seven days at 37C after irradiation.
The plastic materials for the preservation of irradiated food in China are still in the beginning. Recently, onion, garlic, mushroom, potato sausage, rice and its products have been approved to be preserved by irradiation. Hollow plate production line www.handern.com

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