Fresh keeping film of compound coating machine
DATE：2021/4/6 9:19:47 / READ： / SOURCE：This station
Fresh keeping film of compound coating machine
According to the statistics of the food and Agriculture Organization of the United Nations in the 1990s, 30% of the world's food has been abandoned due to corruption. Meanwhile, 300-500 million people in the developing countries of Asia, Africa and Latin America are hungry. In order to solve this contradiction, it is important to use packaging technology to prevent food corruption. Fresh food packaging is an important packaging technology to prevent corruption and extend the shelf life of food.
As we all know, fresh food can be frozen and refrigerated for a long time to keep food from spoilage; removing moisture to keep food dry can also inhibit the reproduction of spoilage bacteria in food; salted or vinegar food is another way to preserve food to prevent spoilage. The fresh-keeping film uses the certain degree of air permeability of the film to make the fresh food inhale O2 and discharge CO in the fresh-keeping bag, With the passage of time, the amount of CO2 in the bag will increase due to the respiration of fresh food cells, while O2 will be less and less. When CO2 is more than 7% and O2 is about 2%, the respiration of fresh food in the bag will become weaker and weaker, and the cells will be in the "hibernation" state. Due to the certain degree of air permeability of the fresh-keeping bag, the gas components in the bag can be preserved for a long time At the level of hibernation, it can keep fresh. The preservative film must also have the function of preventing a large amount of water in the bag from evaporating and escaping, preventing the water from agglutinating on the inner membrane of the bag and dropping on the fresh food; if it is fragrant, the dripping water will cause the fresh food to rot. The preservative film should also have a certain degree of self-adhesive, which can easily wrap food. Production line of compound coating machine www.handern.com
There are two main types of fresh-keeping, one is PVC, Because a lot of plasticizers are used in PVC fresh-keeping film, in Europe and the United States, even non-toxic plasticizers are required to transfer less than 10mng / DM to food. Moreover, PVC is difficult to process, and its moisture resistance is not as good as polyolefin. In addition to PVC, PVDC is also an excellent material for fresh-keeping film, but its price is relatively expensive. The other kind of plasticizer used in large quantity is polymer light film, which is used for the production of polyolefin fresh-keeping film According to hydrocarbon tree, it is less used. The resin is LDPE, EVA (MRF 0.3 ~ 0.6g/10min, VA content < 25%) and LLDPE. In order to make the policy shares have a certain degree of self-adhesive, we can add about 0.5% - 1% of vegetable oil: soybean oil, cotton oil, polypropylene and other materials in the polymer resin. In order to prevent water drops, we can add them from the source. There are 12 ~ 25 carbon frames, i.e. one side of the oil, with good antifogging property. The method of preservation film can be extrusion blowing method or T-die extrusion casting method. Baojiefu made by baojiefu packaging materials Co., Ltd. has a 12-18d safe storage period when the temperature is below 20c, a 12-18d fresh-keeping period when the temperature is below 20 ° C, and a longer fresh-keeping period when the temperature is below 0 ° C. Production line of compound coating machine www.handern.com
Author：admin