1 Preface \ x0d \ In the early 1980s, nearly 100 domestic carton factories imported corrugated board assembly line production equipment from the United States, Japan, Italy and Taiwan Province Province. The adhesive used is generally starch glue. Starch adhesive is low in price, simple in manufacturing process and fast in drying, which meets the requirements of high-speed production and is widely used in corrugated paper industry at home and abroad. However, the original starch glue has the following problems: the glue is easy to precipitate in the process of use, easy to be moldy and damaged at high temperature, and the adhesion performance is not high. The above reasons lead to the waste of rubber compound in the production process, and the performance of paperboard is unstable, even far below the national standard requirements. In order to enhance its performance, modified starch adhesive was developed abroad in the late 1970s and early 1980s, in which alum, ketoaldehyde resin, amine, sodium hypochlorite, sodium stearate and sodium bisulfite were used to modify starch, and good results were obtained. However, there are some problems in these methods, such as complex rubber-making process and difficult source of raw materials. With the deepening and development of China's reform and opening up, many products need exquisite and reliable packaging, and the packaging industry has higher and higher requirements for the quality of cartons. Therefore, according to the actual situation of China's chemical raw materials, it is of great practical significance to develop a modified starch adhesive suitable for China's national conditions. We use polyvinyl alcohol as a modifier to modify the starch adhesive under simple technological conditions, and the effect is good. The produced corrugated board has stable performance and improved quality. \x0d\x0d\ 2 Experimental part \x0d\2. 1 material \ x0d \ and reagent polyvinyl alcohol (PVA), industrial grade, degree of hydrolysis: 99%, degree of polymerization:1700; Industrial grade corn starch; Industrial grade sodium hydroxide (30% solution); Industrial grade borax. \x0d\\x0d\2.2 Experimental method \x0d\ Glue workshop of Nanjing Carton General Factory, water, starch and sodium hydroxide solution were added to reaction kettle B, stirred, heated to 35℃ and gelatinized as a carrier. Water, starch, PVA and borax are added into the reaction kettle, which is used as the main body after being evenly stirred. Mix the rubber compound in kettle A and the carrier in kettle B evenly, and then send it to the rubber roller in the cardboard production workshop. After sampling, the produced cardboard is sent to the testing department for testing the adhesion fastness in line with GB 5034-85. Figure 1 is a schematic diagram of the manufacturing process of adhesive and paperboard in the production test. \x0d\\x0d\3 Results and discussion \x0d\ According to the above process, 18 kettle rubber (about 13 tons) was produced successively. The adhesive will not precipitate and mold. More than 654.38 million square meters of cardboard were produced. The cardboard produced by each pot of glue should be sampled and sent to the testing department to determine the adhesion fastness. See table 1 for the production test results. Table 1 also lists the performance indexes of the cardboard produced by Nanjing Carton General Factory before and after using modified starch adhesive \x0d\x0d\ 4 Analysis of adhesive mechanism \ x0d \ Some starch needs to be gelatinized in advance. If raw starch is directly mixed with water, it is easy to be layered and cannot be glued. However, if all starch is gelatinized with water, the viscosity of starch paste is too high and the fluidity is poor, so it can not be used in assembly line equipment. When sodium hydroxide is added to the mixture of starch and water, sodium ions in sodium hydroxide combine with hydroxyl groups in starch molecules, which breaks some hydrogen bonds and weakens intermolecular forces, thus reducing the gelatinization temperature. Starch can be gelatinized at a lower temperature (35℃), while the gelatinization temperature of corn starch is 62 ~ 72℃. Polyvinyl alcohol is the only polyhydroxy polymer that can be dissolved in water. Excellent film forming and emulsifying properties. The adhesive layer has high strength and good toughness. Its solution has strong adhesion to porous and absorbent surfaces (such as paper). Starch and polyvinyl alcohol in the main body are uniformly suspended in a paste composed of water, borax and a carrier. In the process of limb daubing, starch glue can be evenly coated on paper. Due to the heating and pressing of rubber roller and subsequent drying, the original starch gelatinized and its viscosity increased rapidly. Polyvinyl alcohol gels under the action of temperature and borax, and the film formed after drying has greater strength, thus improving the adhesion fastness of cardboard. \x0d\\x0d\5 Conclusion \x0d\( 1) PVA was used to modify the starch adhesive for corrugated board. Raw materials are easily available, and the factory can produce without adding any glue making equipment. The adhesive has simple manufacturing process and easy operation. \x0d\(2) The modified starch adhesive does not precipitate and mildew, and has stable quality, convenient use and long service life. The adhesive fastness of corrugated board made of it is over 6 0kg 10cm2, which completely meets the national standards. \x0d\(3) The application of modified starch glue can improve the quality of corrugated boxes and prevent goods, especially export goods, from being damaged in transportation turnover, which has certain economic and social benefits.