Selection of commonly used binders for modern binding

Adhesives are one of the main materials used for book binding. The selection of adhesives has a direct bearing on the quality of the processing of the book. If it is properly selected, the finished product of the book will be firm and smooth, otherwise it may cause serious quality problems. Adhesive A substance that binds two objects firmly is an important material that is indispensable in binding. Some books such as wireless glue books are all bound together with adhesives. There are many problems in many areas of the country due to the improper selection of binders or unreasonable use of the binders. For example, three sides of the hardcover book ring village are not sticky (flash), the warpage of the book shells is uneven, and the wireless rubber staples are missing or missing pages. The inequalities in rubber soles and books and rubber buildings are extremely serious. Unqualified products appear and the society has a great deal of scrutiny, which should attract the attention of all parties. Based on these circumstances, I will introduce the type, performance, and use of binders for use by our peers. First, the synthetic resin binder Synthetic resin, also known as synthetic resin, is the monomer by the gathering or polycondensation resin. Synthetic resin adhesives are widely used, convenient, and wide variety of adhesive materials. There are mainly the following for book binding. 1. Polyvinyl acetate (PVAC) bonding material Polyvinyl acetate is a polymer that is polymerized from vinyl acetate monomers. According to different polymerization methods, it can be divided into two types: emulsion type and solution type. The type of emulsion used for binding is milky or white plastic because of its color and whiteness. 1 Performance of Polyvinyl Acetate PVAC is a milky white viscous liquid that is slightly acidic. It can dissolve in many organic solvents, and can resist dilute acid, dilute alkali, not be afraid of pests and bites, not mildew, and harmless to human body. PVAC cured adhesive layer is a colorless transparent body, it does not cause pollution to paper, etc., and it is an aqueous solution, so it is easy to wash, and its viscosity can be arbitrarily adjusted. Easy to use. The PVAC adhesive layer has good toughness after drying, and the cutting does not damage the blade. It is very suitable for binding. This kind of glue has many advantages, but the disadvantage is poor water resistance and poor heat resistance. However, as long as you take care of its performance without any influence, it is the longest time to use (bookbinding has been used for more than 20 years), the most A popular and popular synthetic resin bonding material. 2PVAC Adhesive Indicators The quality indicators for PVAC adhesives currently produced in China are: milky white thick liquids with no obvious particles in the body: solids content 50%±2%: viscosity 1 to 2 microns; pH value 4 to 6: validity period For one year (keeping well for one and a half years). Use of 3PVAC Adhesives PVAC Adhesives are used in a wide range of applications and are particularly suitable for the bonding of porous materials such as paper, fabrics, cardboard, leather, wood and the like. The following points should be noted when using: A. Before use, the adhesive with required viscosity can be prepared with cold water (not lower than 0°C) or hot water (not higher than 36°C). The more water you add, the lower the viscosity, and stir evenly when adding water. B. It can be used for single and double-sheet paper, paste back, sticky book backing, bag cover (paperback), etc., with good adhesive effect. C. can be mixed with flour paste, carboxymethyl cellulose, etc. to increase the consistency of the fluid and reduce costs. D. During winter use, care should be taken to prevent cold and summer heat protection. Do not store and use it below O°C and above 36°C for a long period of time. Otherwise, limbs will deteriorate and precipitate. In order to prevent cold, suitable amount of dibutyl phthalate can be added. E. After using the remaining glue should pay attention to the seal (especially after the open bucket) is not in contact with the air, the plastic surface is best to pour some cold water, to avoid the dry knot hardness to achieve a waste. F. paste book shell is best not this glue. Because PVAC is a water-soluble binder, the drying speed (same as rough surface paste) is slow, the penetration is strong, and it is not easy to set. After the paste, the book shell will be deformed due to moisture penetration and delay the drying time. . After G.PVAC adhesive is mixed with 504 glue, the adhesive PVA coating cover and ring liner paper have a very good effect. The drying of PVAC adhesive depends on the evaporation of water. The drying speed is directly related to the temperature and relative humidity. The drying speed is relatively slow: if it is used in the linkage production line, it needs to add drying equipment, such as far-infrared ray, high-frequency medium heating, etc. Dry temperature cannot be too high. 2. Polyvinyl alcohol (PVA) bonding material Polyethylene acid bonding agent is a white flocculent or powdery polymer compound that dissolves in water and is a clear, colorless, viscous liquid after melting. 1 PVA adhesion performance PVA performance is determined by the structure and degree of alcoholysis of polyvinyl acetate. When the degree of alcoholysis reaches 99% to 100%, a highly crystalline polymer can be obtained, and its water resistance is excellent; when the degree of alcoholysis is 87% to 89%, it is easily soluble in water; when the degree of alcoholysis decreases, The solubility of water is reduced again. The PVA with a high degree of polymerization has a large molecular weight, a good film forming property, a high viscosity, and a strong viscosity, but has poor water solubility. The degree of polymerization is divided into high, medium and low categories, ie, 500 to 700 is a low degree of polymerization: 700 to 1500 is a medium degree of polymerization: 1500 to 2000 is a high degree of polymerization. For binding PVA binders, it is necessary to consider both the degree of polymerization and water solubility. 2 Use of Polyvinyl Alcohol When using PVA adhesive, add hot melted viscous liquid when using it. Its use methods and precautions are as follows: A. Use according to the required viscosity, add proper amount of water in the gel, and place it in the container to heat evenly. Sticky liquid, when heating, use steam or water bath method, not directly contact with the heater, heating temperature within the glue shall not exceed 100°C to prevent aging and deterioration. B. PVA use temperature is 45°C±10: It can be mixed with flour paste under appropriate temperature. C. PVA is heating glue, water is not easy to infiltrate, drying is slow, adhesive cardboard, paper, fabrics, etc. are available, hardcover book case can also use this glue. Polyvinyl alcohol adhesive materials are inexpensive and have good bonding properties. They are extremely common adhesives. 3. Hot Melt (EVA) Hot melt adhesive is a 100% soluble polymer that does not require solvents and does not contain moisture. Heat-melting is a solid at room temperature, and it melts and touches a certain degree and becomes a fluid with a certain viscosity: the melted hot-melt adhesive is a light-brown translucent body. 1 hot melt adhesive composition. The main component of hot-melt adhesive is EVA resin, which is the object of high temperature polymerization of polyethylene and vinyl acetate. After being fused with rosin, glycerol, polymerized rosin, paraffin, etc. at high temperature, it is cooled and solidified into a block of colloid, that is, binding. Bulk or granular hot melt adhesive. The main component of hot-melt adhesives is EVA resin, which is replaced by imports because of its difficulties in polymerization processing in China. 2 Hot-melt Adhesive Performance EVA is 100% solid glue, which turns into a fluid that melts completely by heating at high temperatures. When heated to 80 °C ~ 100 °C, the colloidal slow movement, with the increase of temperature, the flow gradually accelerated, when the temperature rises to 250 °C, the colloid aging, darker color, viscosity decreased, glue change clothes. The colloidal solidification process of EVA is completed by cooling. It is an excellent fast-curing adhesive material, and its drying speed is unmatched by any kind of adhesive material. 3 The use of hot-melt adhesives EVA can be bonded to both porous and non-porous materials, and should not be too large for the adhesive surface. Otherwise, it will not be able to be bonded because the glue cure time is only a dozen seconds at most. EVA is mainly used for high-speed production of wireless glue-binding linkage line, can not be used for manual binding operation. A. When you use it, you need to store enough glue in advance and heat it more than 2 hours in advance to make it gradually become the required fluid. B. The fluidity of the colloid can be controlled by temperature. When the viscosity is high (thick), the temperature can be slightly lowered. When the viscosity is low (thin), the temperature can be adjusted higher. In the perfect binding machine, 150°C～180°C can be used for primary coating, and the temperature of second time (applicator with sticky backing paper) is about 30°C higher than the first adhesive temperature, that is, the viscosity of the second coating is absolutely It is not possible to pull down the first time the book is attached. C. Hot-melt adhesive curing time is generally 7-13 seconds: cooling time is generally about 30 seconds. In the linkage production line, the cooling process is realized by an extended conveyor belt method. In a certain period of time, it is necessary to ensure that the colloids have a good condition of cooling and drying, so as to ensure that the books are firmly bonded and beautifully flattened. D. The conditions for the production of hot-melt adhesives should be to ensure normal room temperature. If the room temperature is too low, the curing time will be affected. The adhesive will fall off due to premature drying and the adhesive bond is not strong (or sticky). 3. Paper-plastic composite materials This material is a copolymer of acrylate and styrene, the appearance of milky white liquid. Its colloid has good adhesive properties and required viscosity and film elasticity. The paper-plastic composite binder uses water as the dispersion medium (water solvent), is non-flammable, non-toxic, harmless, and has no irritating odor. It is a water-soluble adhesive material with convenient use and strong bonding ability. This adhesive is more widely used with the change of the material for framed materials (such as PVC coating paper, cover paper, plastic cover, etc. in the cover material), and it must be used for the connection of elbows to the paper, especially the cover of the upper material. The glue between the hardcover shell and the ring lining can stick with the glue if the three sides are not sticky. Paper and plastic composite adhesives can be used for manual binding and machine binding. It is easy to operate, with high viscosity and firm bonding. The adhesive was mass-produced in the mid-1980s with good results and popularity, and solved the problem of the non-stick quality of the three-ring liner. Second, animal bonding materials The use of animal bonding materials has a long history in China. As early as more than 2,000 years ago, people used animal skins and water to make skin glues for various objects. This glue is a cementitious material obtained from the skin, intramuscular tissue, and bones of hot water or mortar-treated animals. The types of animal adhesive materials include bone glue, gelatin and fish glue. Glue is commonly used for binding. Fish gelatin has a wide range of uses for dried fish. Therefore, it is basically not used to make cement. 1. Bone glue is one of the most widely used animal adhesive materials. Its characteristics are: good bonding performance, high strength, low moisture, fast drying, good bonding and shaping, and low price, easy to use, especially suitable for bonding and pasting hardcover book shell, can get good results. 1 The properties of bone glue The main component of animal glue is gelatin skin protein. Its low purity is called bone glue. Bone gum is a brittle hard block solidified body. Collagen is a protein that is insoluble in water. After being heated and treated, it becomes another form of protein called gelatin, which is soluble in hot water and has adhesive properties. The plastic film of bone glue is very firm and elastic after forming: But the glue is not water resistant, and the water will make the adhesive layer expand and lose the adhesive strength: its corrosion resistance is also poor, and the temperature is too high and the humidity is too large can cause changes. 2. Use of bone glue When using bone glue, soak the bone glue with equal or slightly more water (preferably with hot water) for about 10 hours to soften the glue and heat it to about 75°C to make it glue. be usable. The ratio of glue to water should be based on the desired viscosity. For example, the viscosity of water is low and dilute: when water is added, the viscosity is high and thick. When the hot glue temperature should not be too high, the temperature exceeds 100 ° C will be due to molecular degradation and viscosity, gum aging deterioration. Bone glue has a small amount of sedimentation during use, so use the side well to add the necessary agitation to adjust the viscosity and fluidity. Heat bath must be used bath heat method, and can never be directly heated storage container. The glue can only be used under certain temperature conditions. Therefore, when water is added during use, the temperature of the added water and gel should be basically the same, and cold water should not be added. Because the bone glue needs to maintain a certain temperature (75°C±10°C), the temperature of the glue after the cold water is added will suddenly drop, and the stickiness will appear, which will affect the adhesive effect. When using bone glue, the speed of coating is faster and more uniform. Do not use too much silicone rubber to cause problems such as unevenness of the adhesive layer, leaking of the adhesive, and leakage of the adhesive. 2. Gelatin gelatin composition is similar to bone glue, but the purity is higher and the colloid is transparent. The raw materials for making gelatin are high-quality fresh animal hides, scraps and bones. The melting temperature and coagulation temperature of gelatin are different from those of bone glue. Although the purity of gelatin is high, it still contains some plasticizers. These plasticizers can absorb moisture from the air to prevent the adhesive layer from drying too much and become brittle. Gelatin can be added before use