Shenzhen heat shrinkable bag manufacturers talk about the production process of multi-layer co-extruded film

At present, with the industrial upgrading of many domestic industries, which has stimulated domestic demand for multi-layer co-extrusion films, many companies have already or are preparing to launch this project. Due to different understandings of this product, each company has its own formula recognition and understanding. There are also various formulations. For a while, the mother-in-law said her mother-in-law was reasonable, and the public said the state was justified. Therefore, the author recommends himself, and conducts an objective and fair analysis of some of the situations I have already understood for your reference. Some time ago, a friend came to consult the author on how to produce nylon film for packaging in the electronics industry. And they commissioned some domestic factories to make some samples, and analyzed from the results of the tests, it was found that the 12-thickness wire could not meet its requirements. The structure is PA/TIE/LLDPE/TIE/modified PE, and the nylon content is 20%. Test method, poke with a ballpoint pen. The author believes that, first of all, this test method is not desirable. The test should be carried out in a scientific manner and with the correct method, so that the tested data is authentic and can be used as a reference for process shaping and improvement; secondly, from the analysis of the structure, the structure is feasible, and the product application field may have errors; Third, this friend of the author did not explain the true situation to the author, so that the author has no idea of u200bu200bthe problem. Therefore, the author cannot make a correct answer. The author’s friend’s question is very representative. There are different opinions on the formulation and prospects of the production process of nylon film in China. Some say that it will be replaced by a seven-layer high-barrier film in the future. How is the structure not good? Some people say that it will be like the CPP, BOPP, and BOPET industries. In the end, everyone will fight for the cost and market price, and both will lose. No one can ask for a bargain. The author believes that no matter from which point of view, if we pay attention to the maintenance of the technical level, then we can maintain the core competitiveness of the enterprise in the market competition. Therefore, based on years of working experience, the author has screened and sorted out some information collected over the years. The following analysis and judgments are made: 1. Structure design 1. Casting process, mainly PE/TIE/PA/TIE/PE. The advantage of this structure design is to ensure the flatness of the film and the overall use of the film The function is not destroyed (nylon is hygroscopic), and curling is not easy to occur; mainly in Guangdong Zhongshan Xiangfu and Changzhou Haiqi and other companies that use the casting method. 2. Film blowing process, (1) up blowing, PA /TIE/PA/TIE/PE, the author's research on the cited structure should be proposed by Dalian Sun Gong. This kind of film is mainly to eliminate the problem of reducing the crystallinity of the film during the cooling process, so that good transparency can be achieved to compensate Disadvantages of air cooling (insufficient and fast cooling). (2) Down-blowing method, PA/TIE/PE/TIE/LLDPE (EVA) and PE/TIE/PA/TIE/PE two kinds, because the down-blowing method is similar in cooling mode to casting, therefore, in the early structure Most of the design uses the same structure as the casting method. In the later period, especially in recent years, factories began to use the PA/TIE/PE/TIE/LLDPE (EVA) structure for production. The author believes that no matter which process is used for production, rationality should be considered in structural design, and there is no absolute difference between good and bad. In other words, whether it meets the requirements of customers, the simpler the structure design, the better. Don't overcomplicate the structure design in order to increase the buying point or prevent competitors from copying. This may cause you to find yourself in the quality and production process control. trouble. 2. Material selection 1. Nylon materials. At present, the nylon materials used in the production of films are mainly imported materials. The main suppliers are DSM, BASF, DUPONT, Mitsui, Toray, Mitsubishi, etc., with BASF, DUPONT, DSM The most used materials. Commonly used mainly include BASF's B36LN, B40, DUPONT's SelarPA, etc. In the choice of nylon materials, one or two materials cannot be fixed, and should be selected and matched according to the specific use of the product. For example, in the casting method, if the thermal stretch forming cover film is produced, in order to maintain the film For dimensional stability during use and to eliminate curling, SelarPA20%+homopolymer PA can be used as the outer PA material. 2. TIE (adhesive resin), the data collected from the author at present show that DUPONT 30E671 is used most. Of course, there are other brands of products that can be substituted, such as SK's LE350V, and Guangdong Lushan's products. 3. PE material. Because there are many grades of PE products, only the author's preferences are listed for your reference. LLDPE is SK's FV149, LDPE is Shanghai Petrochemical's Q281 and Q200, or C8LLDPE. From the author's years of experience in the industry, I believe that I prefer to use FV149+EVA blended materials in heat sealing. Such cooperation can increase the flexibility and dimensional stability of the film in the up-blowing method. At the same time, transparency has also improved. In addition to ensuring the correct selection of the above design, consideration should also be given to parameter design issues in the mechanical production process, such as the temperature setting of the extruder. The author believes that the temperature difference between the heating temperatures in each zone should not exceed 10 degrees, so as to ensure the materials of each layer It will not affect each other due to the excessive temperature difference, and cause trouble in the extrusion and cooling process, thereby causing problems such as uneven layer thickness and streak phenomenon. In addition, in addition to these purely technical issues, the author believes that in the process of making process formulas, the production cost of the product and the issue of material loss should be considered together, so as to ensure the market acceptance of the product and prevent the company's products from being Under the impact of competitors in the market! 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