Application status and development trend of the ho

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Application status and development trend of polyester in packaging field

application status and development trend of polyester in packaging field

May 5, 2001

polyester is the general term of thermoplastic saturated polyester represented by pet, including PBT, pen, PCT and their copolymers. Among them, pet is the polyester product with the earliest development, the largest output and the widest application

polyester can be divided into fiber and non fiber according to its purpose, and the latter includes film, container and engineering plastics. Polyester

is mainly used to manufacture synthetic fibers in the early stage of development (accounting for about 70% of pet consumption). Polyester is also used to make edge materials, tape bases, film or photographic film bases and vacuum packaging. Another key point of polyester non fiber application is the manufacturing of hollow containers for filling beverages, food, etc. Secondly, polyester is also used as an engineering plastic in the fields of electronics and electrical appliances, such as meter cases, hot air masks, etc. Among them, the development of packaging containers is the most eye-catching. Now more than 20% of pet has been used as packaging materials, and it is increasing year by year. The packaging industry has become the second largest consumer of pet, second only to synthetic fiber

because pet products that are basically amorphous, highly transparent and easy to stretch can be easily obtained by rapid cooling, when used as packaging materials, pet can be made into biaxially stretched packaging films, high-strength and highly transparent stretch blow molding bottles can be obtained from amorphous bottle blanks, and can also be directly extruded or blown into non stretched hollow containers. Pet

film has the properties of transparency, oil resistance, fragrance retention, sanitation and reliability, and a wide range of use temperatures (high-temperature cooking and freezing package

), but its thermal sealing property is poor, and it must be used in combination with other films (thermal sealing layer), and the price is relatively high. However, its performance can only be achieved by the operation of computer servo system, which limits the application of PET film in packaging. PET hollow containers, especially stretch blow molding bottles, give full play to the performance of pet, have a good display effect on the contents, and the cost is low. Therefore, when pet is used as packaging material, it is usually formed by stretch blow molding. Among them, the most widely used are small bottles with a volume of tens of milliliters to 2 liters, as well as large bottles with a capacity of 30 liters

beverage packaging. In beverage packaging, carbonated soft drinks (CSD) are the most successful in the application of polyester bottles, such as Coyle, Sprite, etc. CSD bottles have accounted for 1/3 of the total PET bottles. PET bottles have beautiful appearance, flexible design, high strength, good sealing to carbon dioxide and reliable hygiene, making polyester bottles an ideal packaging container for CSD, which is widely used by CSD

super energy saving and emission reduction in the beverage industry. The statistical data of China Beverage Industry Association in 1998 showed that PET bottles accounted for 57.4% of CSD beverage packaging in China, followed by cans and glass bottles, accounting for 31% and 7% respectively

edible oil packaging. PET bottles are oil-resistant, transparent, non-toxic, tasteless, not easy to break, good barrier to oxygen

and good shielding against ultraviolet rays, which can protect edible oil from oxidation and deterioration for a long time. Foreign countries have successfully applied

, and the domestic demand for this aspect has been rising in recent years

packaging of seasoning commodities. Liquid condiments such as soy sauce are a huge potential market for polyester bottles. PET bottle has the advantages of good fragrance retention, light weight and not easy to break, which are the advantages of its application in this field. As early as 1995, Japan's application in this area has exceeded 30000 tons, accounting for 13% of the total consumption of PET bottles. Such goods in China are still mainly packaged in glass bottles, and the application of polyester bottles is still in its infancy

beer packaging. In the world, the use of plastic bottles instead of glass bottles for beer packaging is still in the development and trial stage. Relevant departments and enterprises in China also pay more and more attention to the development of beer plastic packaging

packaging of pesticides, pharmaceuticals and daily chemical products. Polyester bottles can be used for the packaging of some pesticides. The low-cost pet pesticide bottles produced with polyester have been put into production in China. PET bottles are safe and hygienic, with good moisture-proof, oxygen isolation and display function, which makes PET bottles applied in the field of pharmaceutical packaging. Cosmetics, detergents and other daily chemical products are also a huge market for the application of polyester

bottles. PBT and pen bottles have good chemical resistance, fragrance retention, high transparency, shielding against purple

external lines and flexibility in shape design, which are the expected characteristics of cosmetics and other daily chemical products. Therefore, polyester

bottles are widely used in the packaging of daily chemical products, especially the new gas barrier and UV shielded pen resin bottles will play a role in the packaging of perfume

water and cosmetics

With its superior performance, relatively low cost and adaptability to environmental protection, PET bottles have developed rapidly in the competition with other packaging materials (glass, tinplate, PE, PVC, etc.), but its heat resistance and gas resistance are poor, which limits its application in hot filling and occasions requiring high air tightness, and has attracted great attention. In the process of improving its performance, polyester packaging has achieved new development

first, improve heat resistance. Ordinary PET bottles cannot be used for the packaging of fruit juice, tea and other items that need to be hot filled. At present, through the research of

, three practical types of heat-resistant polyester universal tensile test motor sub tensile machine have been developed. It adopts a full digital, closed-loop (force, deformation, displacement) control system based on Neuron Adaptive PID algorithm. Bottles: thermosetting bottles, which can meet the requirements of 85 ℃ filling

pet/pen alloy bottle, pen has high heat resistance, and can be made on ordinary injection, drawing and blowing equipment to meet the requirements of hot filling above 80 ℃

. If it is heat set again, the hot filling temperature can reach above 90 ℃; Made with heat-resistant polyarylate, etc.

multilayer composite bottle to improve heat resistance

the second is to improve the gas resistance. Although the gas barrier property of pet is much higher than that of polyethylene, polypropylene, polystyrene and other plastic materials, it still cannot meet the requirements for beer, Baijiu, perfume and other products with strict requirements for fresh-keeping and flavor preservation. There are three main methods to improve the high gas resistance. First, multi-layer composite, mainly pet, with the addition of PVDC, EVOH and pendulum, a certain potential energy m xd6,

pen and other materials with good air tightness can be made into 3-layer or 5-layer bottles. The second is to adopt special treatment methods, such as coating epoxy barrier layer inside or outside the PET bottle, or plasma treatment (ACTIS Technology). Third, it is molded with other barrier tree

fat, and takes pen or the copolymerization or blend of pen and pet as raw materials, which not only improves the gas resistance of the bottle, but also improves the heat resistance of the bottle, which can meet the requirements of beer storage for 3 ~ 6 months, but also can be alkaline washed, disinfected, reused, and reduce the cost from

. Because the first two methods have problems such as poor transparency, difficult recovery and treatment, complex process, special equipment requirements

, and although the air tightness is improved, the heat resistance is poor, which can only be suitable for sterile filling. China's beer industry mostly adopts the pasteurization technology after filling, so using pen or copolymerization and blend with pet as the raw material and molding through the current pet bottle blowing equipment and process is the development direction of beer plastic packaging suitable for China's national conditions, which deserves the attention of relevant departments and enterprises

polyester packaging material is the most dynamic and promising material among all kinds of packaging materials, and it is also the fastest-growing field in many

application fields of polyester. Polyester, led by PET and pen, has become the mainstream material for packaging drinks such as CSD, water and fruit juice, and will also become one of the packaging materials for beer, edible oil, cosmetics and other products

the development of polyester packaging in China began in the 1980s, and bottle grade polyester and polyester bottles started late, but the polyester packaging industry in China is developing at a high speed. In recent years, CSD, pure water, fruit juice and other beverages in China have increased by more than 20%. Therefore, the demand for polyester bottles for beverage packaging has also increased by double digits. At the same time, the demand for bottle grade polyester in non food packaging markets (such as cosmetics, pharmaceuticals, pesticides, etc.) is also quietly increasing. The consumption of bottle grade polyester in China was 120000 tons in 1996, 180000 tons in 1998, and 300000 tons in 2000 according to preliminary statistics. It can be seen that China is the market with the greatest packaging potential for bottle grade polyester and polyester

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