The current situation and development trend of dom

The current situation and development trend of domestic flexible packaging raw materials (Part 2)

the inner material of composite membrane is in direct contact with packaging items, and it needs to consider the adaptability, permeability resistance, good heat sealing, transparency, openness and other functions of packaging items. In China, the development of composite film inner layer materials has experienced three stages: LDPE ordinary film to CPP film, and now coextrusion film is widely used, which makes the composite film inner layer materials enter a new period of rapid development and functionalization. LDPE or LDPE and LLDPE BLEND resin was first widely used in China. The inner film produced has good heat sealing and moisture resistance, and is still widely used in food packaging such as convenient paintings, biscuits, milk powder, pickles, pickles, and mustard; In the early 1990s, a large number of casting equipment were introduced in China, and a large number of casting CPP films entered the packaging market. Because CPP has good heat sealing, high-temperature cooking resistance, oil resistance, transparency and aroma retention, it further expanded the application scope of flexible packaging materials, and is widely used in the packaging of meat and other foods that need high-temperature cooking and sterilization, puffed foods and small foods (such as shrimp chips, potato chips, popcorn, etc.); Metallocene LLDPE is successfully developed by Dow Chemical Company. It has good blending and easy processability with LDPE. This kind of blend blown or cast film has better anti sealing pollution, low temperature heat sealing, better impact strength and tensile strength. At present, it has been widely used in liquid packaging and ultra-fine powder packaging such as frozen and refrigerated food, shampoo, alcohol, oil, vinegar, etc., solving the problems of packaging production Problems such as package breakage, package leakage and penetration during transportation; Coextrusion composite film makes flexible packaging materials truly functional and personalized. According to the requirements of the performance, state, composition and storage conditions of the contents, manufacturers can have a wider space to customize the packaging structure to ensure that the food maintains the necessary quality and safety and is delivered to consumers, such as the application of high resistance heat insulation sealing materials and the application of heterogeneous heat sealing materials. In the past two years, the development of single center Mao catalytic resin and the advent of easily expandable foldable blow molding die have been successful, The coextrusion coincidence membrane has been brought to a new stage of development

bony film is widely used in the packaging of high-temperature cooked food, boiled food and vacuum food because of its special properties such as softness and puncture resistance. However, at present, the domestic capacity is far from meeting the market demand, and the price of bony in the market has always been high, and a complete buyer's market has not been formed. Japanese and Korean products occupy a larger market share. The production capacity of domestic bony will be doubled in 2003, This situation will be fundamentally changed, and flexible packaging enterprises can also enjoy better product price services when purchasing bony

adhesives

at present, the adhesives used in the flexible packaging industry include one-component polyurethane adhesives, two-component polyurethane adhesives, acrylic adhesives, solvent-free adhesives, alcohol soluble and water-soluble polyurethane adhesives. The development of China's flexible packaging industry is closely linked with the technological progress of domestic two-component polyurethane adhesives. At present, the production capacity of domestic two-component polyurethane adhesives for flexible packaging is nearly 50000 tons, and the actual production was about 30000 tons in 2002. Ordinary adhesives and some functional adhesives can be completely localized. The two-component polyurethane adhesive with 75% solid content accounts for 60% of the market share, and the market of the two-component polyurethane adhesive with 50% solid content is shrinking, but it still accounts for more than 30% of the market share officially offline in Pudong base, the newly built final assembly manufacturing center of COMAC. In the special adhesive market with less than 10%, imported adhesives still occupy an advantage. Domestic adhesive enterprises have become mature, their technological development strength has been greatly enhanced, and their products are developing towards functionalization, accounting for more than 80% of the domestic market share. The market competition has also transitioned to the stage of low profit and order. Leading enterprises in the market, such as Beijing GAOMENG, Beijing Chemical Research Institute, Huangyan New Oriental, have emerged. These enterprises have the ability to develop and produce functional adhesives by themselves and have been verified in the market. The flexible packaging materials in China are mainly dry-type composites. The rapid development of dry-type composites has brought great changes to the packaging industry and achieved great economic and social effects. The two-component polyurethane adhesive used in this composite process is mature and cheap. Its disadvantage is that a large amount of solvents are emitted to pollute the environment. In addition, in the composite process, a small amount of residual solvents are left in the substrate room according to the needs of vehicles, which will produce peculiar smell in the package in serious cases. Under the impact of the current tide of environmental protection, environment and development have become a major issue of general concern in the world today, so foaming products with a wide range of hardness can be made. Countries have launched a revolution to protect the environment and reduce pollution. Under this background, traditional polyurethane adhesives have been challenged unprecedentedly, and foreign companies have also introduced environmental friendly adhesives to the Chinese market, Domestic leading enterprises have also made meaningful exploration on environmental friendly adhesives. In a fairly long period of time, polyurethane adhesives will still occupy most of the market share in China, and the amount of solvent-free adhesives will increase significantly in the short term, but there will not be much development. The reason is that at present, the performance, price or equipment investment cost of solvent-free adhesives, alcohol soluble and water-soluble products are not as good as the existing two-component polyurethane adhesives, and the domestic base film materials and equipment conditions can not fully meet the coating and drying requirements of alcohol and water-based adhesives. In addition, the actual national conditions of China are also a reason that can not be ignored, At present, China has introduced more than 30 solvent-free production lines, most of which are in the state of shutdown or semi shutdown. Enterprises with solvent-free production lines are trying to transfer some products to solvent-free equipment for production, which will expand the application of solvent-free adhesives, but expensive equipment investment is too heavy for enterprises. In recent years, the introduction momentum of domestic solvent-free production lines has been significantly weakened. Flexible packaging enterprises and adhesive production enterprises should not blindly catch up with the latest trends. They must be based on the national conditions and seek truth from facts, and find a new way to make the smooth and healthy development of China's flexible packaging industry and effectively protect environmental resources. Solve some environmental protection problems that need to be solved urgently and can be solved, such as: do not use single component polyurethane adhesive, eliminate the emission of toluene, reduce the use of 50% adhesive, improve the coating concentration, and further reduce the volatilization of ethyl ester. In China, the coating technology of high solid content working concentration, such as plastic bottles and plastic bags, is not very good. Generally, it is best for enterprises to only achieve 35% coating. In addition to products with high transparency requirements, polyurethane adhesives can generally increase the working concentration to 40% to 45%, which is very meaningful to reduce the volatilization of ethyl esters, protect the environment and reduce costs. Adhesive enterprises must closely cooperate with equipment manufacturers and plate roller manufacturers to help composite enterprises improve coating technology. In addition, for solvent-free alcohol and water-based adhesives, the author believes that adhesive enterprises should put their experience in the development of water-based and solvent-free adhesives, and pure soluble adhesives are only transitional products. It is not a real environmental protection product, and its application is limited. Its application in foreign flexible packaging market is also very small. Domestic adhesive manufacturers should take advantage of the advantages of two-component polyurethane adhesives and concentrate on developing functional adhesives to expand greater market space