With flexible packaging materials in China's development, combined with a poly acid adhesive also gone through twenty years of history.
Since the mid-seventies of last century, the Shanghai first developed by extrusion coating and extrusion lamination method to make simple food with complex flexible packaging materials, to the late seventies,paper napkins but also the first to develop with the dry method to produce more high-end complex composite flexible packaging materials for food, simple food from the general production of composite flexible packaging materials, to the resistance to high temperature 121 ℃ 40 minutes cooking plastic / plastic cooking bag and more advanced aluminum / plastic cooking bag. At the same time, it developed simultaneously dry laminating adhesive.
We know that, paper tissue do use the dry method composite flexible packaging materials, in addition to a variety of plastic films and aluminum foil substrate, but also used in adhesives. Is the first to be used in butyl rubber-component solvent-based pressure-sensitive adhesive to do, use it to PET, PT, and these types of PE film composite can be made up to the simplest, most primitive composite flexible packaging material, used in hard tack, the packaging of candy and mustard. To the late seventies, due to the development of resistance to 121 ℃ 40 minutes of cooking temperature cooking bags, one-component adhesive is obviously not, so, Shanghai has developed the first high-performance two-component polyurethane adhesive. Of course, this adhesive in our country there is already industrial products in the sixties, but because its performance does not meet the requirements of flexible packaging, there is a high boiling point solvent, a serious odor, too much residual monomer, health performance is not reliable initial viscosity is too small and other shortcomings, not in the dry compound used to make qualified in food packaging materials, so the United States, Japan, the level of the target was re-meet food hygiene and safety research and development, can withstand 121 ℃ 40 minutes of cooking two component polyurethane adhesive. After more than two years of study, and finally in August 1981 by the National Science and Technology Commission and the Ministry of Light Industry of the identification, completion of this task.
After 1980, China's gradual reform and opening up, people's living standards have markedly improved, the market economy has become increasingly active, the rapid development of the food industry, the main food increasingly rich, require excellent voice also risen packaging, flexible packaging materials in great demand Therefore, Shanghai, Wuxi and Dalian first introduced from Japan more advanced production line of flexible packaging materials, which combined a number of color intaglio color printing machine, dry laminating machine, bag machine, cutting machine and the corresponding detection equipment, as Modern composite flexible packaging industry in China has played a leading role in the development. However, the production of flexible packaging materials required for gravure printing ink, adhesives, PET, OPP, OPA, CPP, aluminum foil, etc. to be imported.
In order to meet the needs of the domestic production of flexible packaging, since the last century, first half of the eighties began, around the country and to develop flexible production equipment, Shanghai, Wuxi, Haining, Guangdong and other places of flexible packaging machinery manufacturing enterprises, rapidly developed, complex Printing of flexible packaging material production enterprise is also booming, leading to imports of gravure inks, dry adhesive composite soared soaring demand. In this situation, the Shanghai composite packaging materials with food production technology with a polyurethane adhesive, there is the soil of industrial production. So, in 1984, first create an annual output of 60 tons of Chinese food-grade scale production base of polyurethane adhesive. With this model the base, so that the adhesive packaging industry localization of hope and prospects, in just two to three years, have two or three places have been built about 500 tons of annual production in the enterprise, officially started the climax of the localization of the adhesive. The mid-eighties of last century, Beijing Institute of Chemical Industry co-operation with the German Henkel, Henkel technical advantage in the domestic production of dry compound with the solvent-based two-component polyurethane adhesive. However, the curing agent of the production technology does not cooperate, but also imported from Germany, and then repackage and supporting domestic production, the main agent used. Later, research and development through their own, with your own production techniques of curing agent before curing agents used in domestic production to replace imported products, and the main agent in the country supporting the use of the production.
Eighties domestic production of polyurethane adhesives technology, while relatively few species, most asked not to be too high for the low mid-range among the composite flexible packaging materials, on the other hand, the quality of some shortcomings, such as glue viscosity is too large, anti- poor frozen, freezing in the winter easy to use when first heated to 50 ~ 60 ℃, it melted before it can be prepared from the packaging operation of the solution down the barrel, then one hand, the film has not many features, stick Relay is not very high, anti-media capability is poor.