Advantages of using adhesives in printing and bind

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Advantages of using adhesives for printing and binding of books, periodicals, pictures and albums. The fluidity of reactive adhesives is viscosity. In many industrial fields where adhesives are used, viscosity value is regarded as an important index of adhesives. We have already mentioned that in order to have good cohesive strength, the agent should have a high molecular weight, generally a high molecular weight polymer. However, there are many ways to make low viscosity liquids meet the needs of coating polymers. Solid polymers can flow freely when heated, such as hot melt adhesive commonly used in bookbinding industry. Another example is that polymers can often be dissolved in cold water or hot water to form water-soluble compounds, or dissolved in organic solvents, or form a kind of emulsion. In short, their viscosity can be changed. However, no matter what type of adhesive it is, the twist value should be controlled within a certain range. For the absorbent material, if the viscosity of the adhesive is too low, most of the adhesive on the surface will be absorbed by the adhesive, leaving only a few dry agents on the surface, which is not enough to form a strong adhesive layer connected with the surface of another dry material. If the adhesive viscosity is too high, the amount of adhesive penetrating into the adherend is not enough, nor is it enough to produce an effective mechanical connection, and it is difficult to apply the drying agent. At the same time, it should be noted that the dryness of the solvent based adhesive will change with the volatilization of the solvent. If the water or organic solvent in the adhesive is likely to evaporate, the adhesive will become thicker and thicker. If appropriate measures are not taken, the adhesive with appropriate viscosity may have a series of faults such as uneven distribution or insufficient penetration of the adhesive to the bonded object due to excessive adhesion. The adhesive is required to have a certain viscosity, so that the cover material can adhere to the book block for at least 5~8 minutes without the two withered objects coming out of contact due to the force of the cover material returning to the original shape. This time is necessary to complete the binding work. The viscosity of the drying agent mainly depends on its cohesive strength. A high cohesive strength of the adhesive can ensure that the adhered object will not stretch, but the adhesive with too high cohesive strength is not easy to spread on the surface of the twisted object

the withering strength of the adhesive is an important indicator of the adhesive, which is generally required to be able to adhere to the materials to be bonded. For example, the bonding of the cover cloth should be able to bring down a layer of cardboard bonded with the cover cloth when the cover cloth is torn off. For paper, when Liu Qiang, chief engineer of Jixiang Automobile Research Institute, wants to tear off a layer of paper, this layer is often not completely peeled off, or the next layer of paper is also taken down

the amount of adhesive shall be as little as possible and sufficient bonding fastness shall be achieved, which requires that the adhesive film applied shall be dense and sticky. In this way, not only the amount of glue used can be reduced, but also the bonding condition is much better than that of thick adhesive film when tightening the head flange nut. The color of the dry mixture should be as transparent as possible. If the color of the glue on the Xu is too deep, the pasted materials, especially the translucent paper and cloth, will change color. If the operation is not careful, a little dark adhesive on the cover will cause conspicuous defects and affect the appearance of the product

the adhesive shall have no unpleasant smell and no harmful gas shall be released during bonding. The acid-base property is moderate or weak alkaline. If there is free acid or too strong alkaline in the glue solution, it will also affect the fastness of bonding or damage the bonded material. The composition of the adhesive shall not contain substances that can fade the ink, otherwise it will also affect the beauty of the printed books and pictures

the adhesive should be free from mold, moth and mouse bite to ensure that the books will not be eroded by microorganisms and animals during storage. Kuji mixture not only has various requirements for finished products, but also its working solution properties can not be ignored. The adhesive working solution also has certain requirements for viscosity, viscosity and concentration, which must adapt to the withered materials and drilling conditions. For example, the stickiness of paper with high adhesion smoothness can be larger than that of paper with low withering smoothness, and the glue of lacquer cloth is thicker than that of cloth used for binding the cover. On the contrary, thick adhesives have more solids, less moisture, and high cohesion, so the bonding strength is high. It is easy to set after drying. However, its liquidity is poor. Check whether the CPU frequency (11.0592Mhz) and the comparison voltage are stable or drift? If there is a problem of faulty welding, it is difficult to infiltrate the surface of the material to be adhered. It is necessary to apply glue with an external force to ensure the full mold lubrication of the contact surface, and it is not easy to penetrate into the interior of the material to be dried. Therefore, the thick adhesive is applicable to the bonding work with small bonding area but requiring large bonding fastness, such as dry sheet, adhesive ring lining, ring chart, table and other sheet paper, as well as wrapping and other operations. The thin withered liquid has less solid content and more moisture, so it has good fluidity and is easy to infiltrate and penetrate into the material after being coated on the surface of the adherend. However, its cohesion is small, its drying property is small, and its bonding fastness is not strong enough. Therefore, it is suitable for bonding the bonded material with large area, such as pasting and sealing the shell, pasting paperboard, mounting pictures and other process operations. It can also be used for the back of the pulp book, which can ensure that the coating is uniform, there is slight adhesion after drying, and the spine will not be uneven after wrapping

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