The hottest German invention of new fresh-keeping

2022-08-05
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Germany invents a new type of fresh-keeping plastic film

the door plate standard of the German Kexin project has been changed from 52388f standard to tl52388h standard. Recently, a kind of plastic film "dyed" by chlorophyll has been invented, which can prevent the oxidation between light and chlorophyll in green food and lead to food decay, thus greatly prolonging the storage time of green food. It is reported that the scientists of Fraunhofer Institute of treatment and packaging technology in Germany "dye" the plastic film with chlorophyll by opening the oil delivery valve in a special way. After this treatment, the film can effectively "intercept" the light that causes food decay when used to package food, thus greatly extending the food preservation period. The new method is not only simple, but also low cost. Most green foods contain a large amount of chlorophyll, which will undergo photosensitive oxidation reaction under light irradiation, decompose the energy in the food and lead to food decay. In order to prolong the fresh-keeping period of food, traditional packaging materials are either opaque packaging materials or plastic packaging and vacuum treatment to insulate food from oxygen. The former can not make customers choose directly, while the latter is more complex and relatively high cost. Synchronous crystal transformation and corona polarization equipment is an important instrument for preparing high-resolution piezoelectric films. 2. Whether the clamping is reliable or not. The piezoelectric strain constants of piezoelectric films prepared by it are much higher than those prepared by asynchronous tensile polarization equipment. Especially with the wide application of PVDF piezoelectric film, the development of this special equipment for piezoelectric film has become a hot spot in the scientific and technological circles and business circles. In order to save time and meet the actual needs of domestic research and production of polymer piezoelectric films, in 1999, with the preferential funding of the Chinese Academy of Sciences, Changchun Yinghua institute undertook the research and development task of "synchronous crystal transformation and corona polarization equipment". They designed polymer film making machine and synchronous tensile polarization device by themselves: that is, it was made of transmission device, feeding device, screw, machine head A polymer film making machine composed of five core parts of the film connecting machine, and a stretching and corona polarization equipment composed of a corona polarization box, a transmission device, a support device and a heating device. At the same time, the key technical problems of the synchronization of crystal transformation and corona polarization of the whole set of equipment have been solved, and then this synchronous crystal transformation and corona polarization equipment has been successfully developed. After the relevant units use this equipment to prepare piezoelectric films, it is determined that its polarization performance is good, the voltage and temperature can be adjusted, and the tensile ratio can be controlled. Among them, the PVDF piezoelectric strain constant can reach 20-34 pc/n, and the instrument is easy to use and has good performance. In addition, it is reported that this special equipment for piezoelectric films has the following characteristics: it can continuously prepare PVDF piezoelectric films by controlling the stretching ratio by using the speed difference and the tooth number ratio and polarizing at the same time; In the processing of PVDF piezoelectric thin films, the processing time is shortened, the polarization temperature is reduced, and the industrialization is easy to realize; The PVDF piezoelectric films prepared by this equipment have excellent piezoelectric properties. The successful development of this equipment has great economic and social benefits. It not only creates good conditions for the mass preparation of piezoelectric films in the future, but also provides a technical and equipment foundation for further industrialization

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