Development and application of the hottest pen con

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Research, development and application of pen containers

polyethylene naphthalate (pen) is a thermoplastic resin with excellent gas barrier, water resistance, UV linearity resistance, heat resistance, chemical resistance, radiation resistance, etc. It has broad development prospects in film, packaging containers (especially beer bottles) and industrial fibers. At present, Eastman company, DuPont company, Teijin company, shell company and BP company have started the industrial production of pen

Figure 1: molecular structure diagram of pen and pet

I. the characteristics and properties of pen

the structure of pen resin is similar to that of pet (see Figure 1). It replaces the benzene ring in pet with naphthalene ring. The naphthalene ring has a larger conjugate structure than the benzene ring, so the molecular chain is rigid, the structure is planar, and its mechanical, electrical and chemical properties are better. See TABLE-1 for the comparison of basic characteristics between pen and pet

pen has similar characteristics to pet, but it is superior to pet in almost all aspects. Compared with pet, pet has the following characteristics: (1) pen film has low thermal shrinkage, good dimensional stability, high glass transition temperature, long-term heat resistance is better than pet, and can be applied to higher processing and use temperature. (2) The gas barrier property is good. Pen is the best among all plastics. Compared with pet, pen has 4 times higher barrier to O2, 5 times higher barrier to CO2 and 3.5 times higher barrier to water. (3) Good mechanical properties. The modulus of pen is 5 times that of nylon, 2.5 times that of polyester and 2 times that of rayon. It can be used for engineering strengthening. (4) The chemical inertia is good, and the ester group in pen molecule will also hydrolyze when encountering water, but its hydrolysis rate is only 25% of that of pet, so its hydrolysis resistance is very good. The stability of acid, alkali and chemicals is also better than pet. It has less adsorption on other substances (such as packaged materials) and low free precipitation. (5) Good ultraviolet absorption

II. Synthesis of pen

■ synthesis route of pen: the synthesis route of pen can be divided into direct esterification method and transesterification method. However, due to the high price of naphthalene dicarboxylic acid, the raw material used in the industrial production of pen is dimethyl 2,6-naphthalene dicarboxylic acid, so now ester exchange method is widely used. The synthesis of pen by transesterification can be divided into two stages: transesterification and polycondensation

■ synthesis and commercialization of pen raw materials: due to the high cost of pen raw materials 2,6-naphthalene dicarboxylic acid (NDA) or 2,6-naphthalene dicarboxylic acid dimethyl ester (NDC), the production and commercialization of pen have been hindered. At present, dimethyl 2,6-naphthalene dicarboxylate (NDC) is the main raw material for the production of pen

in the 1980s, BP Amoco successfully broke through the production technology of NDC, established experimental equipment in 1989, and began to supply NDC in limited quantities. In order to meet the market demand, BP Amoco began to build large-scale production equipment in 1992, and officially commercialized NDC in the United States in 1997. The total investment of the whole project exceeded US $200million

recently, Mobil and Kobe Steel jointly developed a new process aimed at reducing the price of pen. This process combines the zeolite catalyst technology of Mobil company and the new purification technology of Kobe Steel Company, which can significantly reduce the cost of pen

III. commercial application of pen

due to its excellent thermal, mechanical, gas barrier and dielectric properties, pen has a broad application prospect in high-performance thin bone recovery films, fibers, special packaging materials and engineering plastics. Commercial production and application have been gradually promoted

commercial application of T film

compared with PET film, pen is thin, but it is the easy decomposition part of lignin. The decomposition film has the advantages of high strength, high modulus and thermal resistance, excellent gas barrier, hydrolytic resistance, radiation resistance and so on. It shrinks at 190 ℃ and can be used for a long time at 155 ℃, while pet can only be used for a long time at 105 ~ 130 ℃. Pen film effectively expands the scope of application. It is not only the most studied aspect of pen, but also the earliest pen product put into application

Amoco company took the lead in occupying the raw material market of pen film, while Teijin company of Japan first developed and occupied the product market. As early as 1971, Teijin company produced pen biaxial tensile film (bopen) film, and the biaxial hardness tester itself will produce two kinds of errors: 1. The error caused by the deformation and movement of its parts; 2. The error caused by hardness parameters exceeding the specified standards. The trademark of stretched film is named teonex. In April, 1990, the construction of pen film production line with an annual output of 10000 tons began. In addition, Toray, DuPont and other large companies have also entered the field of pen production. Due to the high cost of pen, Therefore, in order to reduce the cost of taking the remaining number of cells [even number] equal to the long segment, a pet/pen multilayer composite film has also been developed.

■ advanced photographic film: since 1996, APS film using pen has been very popular with users, and is gradually replacing the previous silver salt photographic film (raw material is cellulose triacetate). APS film uses annealed pen resin (a-pen) Therefore, the film strength and smoothness are improved. APS film is a magnetic data recording method, and the film base thickness is the same as PET film, but the thickness of pen film is thinner than the previous triacetic acid film, but the imaging is very clear. Eastman Kodak has launched a film with the trade name advantix, and Fuji and Agfa have also launched pen films

■ pen insulating film: bopen film can be used as insulating material for motors, transformers, coils and capacitors, and as vibrating film, film switch and magnetic recording material in communication equipment. Bopen film has stable insulation performance in high temperature and humidity environment, and can be used for a long time at 155 ℃. It is an important variety of thermoplastic high-performance plastic film. Pen film can meet the requirements of class F (160 ℃) insulating film. General PET film can only reach grade e (long-term service temperature is 120 ℃). If you want to reach the long-term service temperature of 130 ℃, you need to significantly increase the viscosity and try to reduce the oligomer content. Otherwise, when used for the insulation of refrigeration sealed motor, it is easy to extract the oligomer by being soaked by lubricating oil, resulting in motor failure. While the mass fraction of oligomer in pen is only 0.5%, which can effectively solve this problem

Figure 2: pen drink bottle

(to be continued)

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