Binding book refers to a method of binding a book with hot melt adhesive without using wire or wire. The quality of the bound book is stable, the error rate is low, the production cycle is short, and the labor intensity is low, which is the future development direction of the binding process. The author here combines the actual work situation of our factory to talk a little bit about the experience of book binding.
The process flow of Binding:
Book block-milling back-slotting-upper adhesive-upper side adhesive-package cover polymer. At normal temperature, the hot melt adhesive is solid, but when heated to a certain temperature, it becomes a liquid with a certain viscosity and fluidity. Its main components are EVA resin, viscosity-increasing polymerized rosin, terpene resin, viscosity-adjusting microcrystalline paraffin wax, antioxidant di-tert-butyl p-cresol, etc. There are many types of hot-melt adhesives on the market, and their performances are not the same. According to the operation speed of the hot-melt adhesive, the speed of the binding machine is different. The low-speed glue binding speed is about 2000 copies / hour, the medium-speed glue binding speed is 2000-4000 copies / hour, and the high-speed glue binding speed is more than 4000 copies / hour. The opening time of low-speed hot melt adhesive is 15-20 seconds, the opening time of medium-speed hot melt adhesive is 5-10 seconds, and the opening time of high-speed hot melt adhesive is 2-7 seconds. The curing time of the hot melt adhesive is 3 to 5 minutes. The opening time and curing time of hot-melt adhesives are closely related to the binding speed of the perfect binding machine. Therefore, it should be selected reasonably according to the type and performance of the hot-melt adhesive. Attention should also be paid to the paper used for binding products, such as hot melt adhesive for coated paper and hot melt adhesive for general paper. The surface finish of different papers is different, and the requirements for the permeability, wetting and thermal conductivity of hot melt adhesives are also different. Therefore, according to the actual choice of suitable hot melt adhesive.
2. The bound version of the bound version of the bound book is different from the bound version of the wire binding, saddle stitching and lock stitching before printing on the machine. , Should be widened to 2 ~ 3mm, this is for the consumption of binding and milling back. Before binding the book block with glue, the binding part should be milled to make the inner two pages of the signature also milled into a single page to ensure the full penetration of the glue. If you encounter a product with a bezel, the outer cut of the book should be drawn on the machine knife before binding, and the size of the outer cut should be widened by 2 to 3 mm during the drawing, so that the product will be booked after milling the glue In order to meet the standards of the finished product.
3. Handling of Bookmarks Before Binding The book block's processing before entering into binding after binding is a process that cannot be ignored in the binding process. The flatness and tightness of the matched signatures not only directly affect the normal operation of the binding production line, but also have a direct impact on the quality of the book. If the signatures are not aligned, they will be unevenly tied and not pressed. In fact, the process of back milling and slotting is transferred. The semi-finished product with defective quality is bound to be uneven even after being clamped by a book holder in the stapler. The immediate hidden danger is the milling cutter. Milling is not in place, the depth of the slot on the back of the book is not good enough, and there are many quality problems such as loose pages, loose pages, empty backs, and missing backs after binding. Therefore, the collation of the signatures is very important. Arranging is to loosen and align the matched signatures, and bundle them. That is, put a certain number of signatures on the strapping machine. The hardwood board is used as the backing plate at both ends of each bundle of signatures. The size of the post is consistent with the size, start the strapping machine, compact the loose post, and then use the strap to bind. In order to stiffen and straighten the spine back of the compacted and bound post, apply a thin layer of polyvinyl alcohol glue on the back of the bundled signature post. After the brushed polyvinyl alcohol glue has dried, loosen the binding rope Open, separate each book, and transfer to binding.
4. The milling back, slotting and slotting of the bound book are the key processes of the bound bookbinding. The milling back is to cut the book block with the signatures along the binding part into flat single pages. Beveled. The slot is to cut the back of the book block after milling, and use a special tool to pull out the groove at a certain distance and depth to increase the permeability and contact area of ​​the hot melt adhesive to the back of the book, so that the pages can be closely adhered. For milling back, the depth of milling should be determined according to the thickness of the paper and the number of folded layers of the signature. Taking 52 ～ 60g / m2 paper as an example, the general milling depth is 1.5 ～ 2mm for the three-fold signature and four-fold signature The core is 2 to 3 mm. The depth of the slot is generally controlled between 0.8 and 1.5mm. If the paper is thick and poor in fiber, it can be drawn deeper, otherwise it can be drawn shallower, but the deepest should not exceed 1.5mm, and the shallowest should not be less than 0.8mm. The shape of the slot is "△", the angle is about 60 °, and the width of the slot is generally 3 to 5 mm, which can also be adjusted appropriately according to the paper. In general, 64 open book blocks can pull 4 to 6 slots, 32 open book blocks can pull 6 to 8 slots, 16 open book blocks can pull 8 to 10 slots, and 8 open book blocks can pull 10 to 12 slots. If the depth of the milling back and the slot of the signature does not meet the requirements, it will affect the penetration of the glue and cause quality defects such as loose pages and loose pages. In addition, while checking whether the depth of milling and slotting is appropriate, the quality of semi-finished products processed in the process of collation, bundling, and compaction before the binding of the signature should also be checked, as well as the situation of glue binding.
5. Precautions for the use of hot melt adhesive The hot melt adhesive should be preheated before use. During preheating, pour the solid hot melt adhesive into the preheated adhesive pot and preheat 1 or 2 at a temperature of about 160 to 200 ° C Hours, after reaching the heating temperature and having good fluidity, put the preheated hot melt adhesive into the glue tank on the machine of 160 ~ 180 ℃, then it can be used normally. The heating temperature of the hot melt adhesive is closely related to the fluidity and bonding strength of the adhesive. Therefore, the temperature of the hot melt adhesive should be strictly controlled, and should not be too high or too low. The heating temperature is best controlled by the technical parameters provided by the manufacturer Within the range, the heating temperature and gluing temperature of the hot melt should be controlled within the range of 170 ～ 180 ℃. If the temperature is too high, the fluidity of the hot melt adhesive is of course very good, and the penetration of the pages is also strong, but the bonding strength will decrease; if the temperature is too low, the bonding strength will increase, but the decrease in the fluidity of the adhesive will make the pages between the pages not firm. Ground adhesion, quality problems such as degumming and loose pages. If the temperature of the hot melt adhesive exceeds 200 ° C, it will cause the carbonization and cracking of the hot melt adhesive. Hot melt adhesives should not be left for a long time. Try to avoid repeated melting and solidification.
6. The top glue and top glue glue the binding position of the book post is the back of the book block and the two sides of the back. After the book block is milled and slotted, the hot melt adhesive can only move the pages between the book block, the book block and the The covers are tightly and firmly glued together. Glue binding is divided into back glue and side glue. Their fluidity, opening time and curing time are different. The adhesive temperature should be controlled at 170 ~ 180 ℃, the adhesive thickness of the adhesive is generally controlled between 0.6 ~ 2mm, the adhesive layer should be uniform, the thin adhesive will affect the bonding strength, the adhesive will be thick, and increase Binding costs. The length of the adhesive glue should be slightly shorter than the cover size of 1 ~ 2mm. If it is too long, it will cause the excess glue to accumulate the mechanical transmission parts, causing malfunctions; if it is too short, it will cause the back of the book and feet to be empty, affecting the quality. The side glue must be brushed when the book block and cover are pasted. The side glue must be a hot melt adhesive with good fluidity, long open time and curing time, and high bonding strength. The temperature of the side glue should be controlled at about 160 ~ 180 ℃. The width is generally 4 ~ 6mm, the side glue should be thin and even, and it needs to be firmly pasted, so as to ensure the quality of book binding and meet the cutting requirements. Do not confuse the use of adhesive and side glue, otherwise it will make the cover of the book cover line, affecting the quality of the book.
As long as you continue to explore and summarize experience from practice, carefully understand the performance of the material, master the appropriate process parameters, and strictly operate the process, you can obtain satisfactory bound quality.
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